Pebble Chin Botox: The Mentalis Evidence, Off-Label Status, Cost, and Risks

When you speak, smile, or pout, does the skin over your chin pucker into a textured, dimpled surface resembling an orange peel or a cobblestone street? In aesthetic medicine, this common phenomenon is known as pebble chin, cobblestone chin, or peau d'orange chin.

Many patients seeking a smoother lower face are advised to receive a few units of botulinum toxin (such as Botox, Dysport, or Xeomin) directly into the chin. While neuromodulator injections into the chin's primary muscle—the mentalis—are widely practiced in cosmetic clinics worldwide, the treatment occupies a unique regulatory and scientific position:

1. It is 100% off-label. A systematic review of all current United States Food and Drug Administration (FDA) neurotoxin prescribing labels reveals that zero FDA-approved toxins list the mentalis muscle or chin dimpling as an approved indication.
2. The controlled trial evidence is remarkably compact. Decades of routine clinical use rest on a single double-blind, placebo-controlled split-chin trial published in 2005 with just 20 patients, supplemented by modern anatomical mapping and observational series.
3. The complication profile is unforgiving. Because the mentalis muscle neighbors the lower lip's primary depressor and sphincter muscles, misdirected toxin can impair your smile, alter your speech, or compromise oral continence for weeks.

Here is the objective clinical reference on how mentalis Botox works, what the published trial data actually demonstrate, why anatomical precision determines safety, what realistic pricing looks like, and when chin dimpling requires filler or surgery instead of a neurotoxin.

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Direct Answer: Does Botox Fix a Pebble Chin, and Is It Safe?

Yes, botulinum toxin reliably smooths dynamic chin dimpling caused by an overactive mentalis muscle, but it is an entirely off-label procedure whose success hinges on precise midline placement.

Dynamic chin pebbling occurs when the paired mentalis muscles contract, pulling the overlying dermis downward and puckering the skin over the mandibular symphysis. Injecting a small dose of botulinum toxin weakens these muscle fibers, allowing the overlying skin to lay flat during speech and facial animation.

However, several critical guardrails apply:

• No US FDA Label Approval: While toxins are approved for glabellar lines, lateral canthal lines (crow's feet), forehead lines, and platysma bands, no manufacturer has pursued or received an FDA indication for the mentalis.
• The Evidence Base: The sole randomized, double-blind, placebo-controlled trial (Beer et al., 2005) demonstrated significant improvement at rest and during maximal contraction compared to saline, though patient satisfaction was complicated by the split-face trial design.
• Signature Complications: Inadvertent lateral or superior diffusion into the depressor labii inferioris (DLI) or the orbicularis oris causes lower-lip ptosis (lip drop), smile asymmetry, drooling, or difficulty pronouncing plosive consonants ("p", "b").
• Duration & Cost: Clinical effect appears within 3 to 7 days, peaks at 2 weeks, and persists for roughly 10 to 14 weeks (approximately 3 months). Costs typically range between $100 and $250 per session, depending on regional unit pricing or tiered area rates.

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What Causes a Pebble Chin: Dynamic Muscle vs. Static Anatomy

Understanding whether neurotoxin will resolve your chin concerns requires distinguishing between muscle-driven dynamic dimpling and skeletal or structural indentations.

                  ┌─────────────────────────────────────────┐
                  │          CHIN CONTOUR CONCERN           │
                  └────────────────────┬────────────────────┘
                                       │
         ┌─────────────────────────────┼─────────────────────────────┐
         ▼                             ▼                             ▼
┌───────────────────┐        ┌───────────────────┐        ┌───────────────────┐
│  DYNAMIC PEBBLING │        │   STATIC CLEFT    │        │  PTOTIC / WITCH'S │
│   (Peau d'Orange) │        │     (Dimple)      │        │       CHIN        │
└────────┬──────────┘        └────────┬──────────┘        └────────┬──────────┘
         │                             │                             │
         ▼                             ▼                             ▼
• Mentalis hyperactivity     • Bony cleft / bifid symphysis • Soft tissue ptosis
• Appears with speech/pout   • Present at rest & movement   • Submental crease laxity
• Superficial dermis tether  • Deep structural cleavage     • Loss of bone support
         │                             │                             │
         ▼                             ▼                             ▼
   [BOTOX / TOXIN]            [HYALURONIC ACID FILLER]       [SURGICAL RESECTION/
 (Relaxes muscle pull)        (Structural fat/HA graft)      SUBMENTOPLASTY / LIFT]

The Mentalis Muscle Mechanism

The mentalis is a paired, dome-shaped muscle located at the tip of the chin. It originates from the incisive fossa of the mandible (just below the lower front teeth) and descends vertically and obliquely to insert directly into the subcutaneous tissue and dermis of the chin pad.

Unlike muscles that connect bone to bone, the mentalis connects bone directly to skin. Its primary physiological functions are:

• Elevating and protruding the lower lip;
• Wrinkling and elevating the skin of the chin during expressions of doubt, displeasure, pouting, or concentration;
• Assisting in oral competence (keeping the lower lip sealed against the upper lip during swallowing and chewing).

When the mentalis is chronically hyperactive, hypertonic, or involuntarily straining to compensate for a weak chin projection (mental retrognathia) or lip incompetence, its dermal insertion points yank the skin inward, creating the characteristic golf-ball or orange-peel texture.

Dynamic Pebbling vs. A True Chin Cleft

• Pebble Chin (Peau d'Orange): Characterized by dozens of tiny, superficial, scattered indentations across the chin pad that become prominent when talking, smiling, or eating. This is purely muscular and responds directly to neurotoxin.
• True Chin Cleft (Central Dimple): A single, prominent, vertical or Y-shaped groove in the midline of the chin. A cleft is caused by an underlying developmental notch in the mandibular symphysis (the jaw bone) or a structural gap between the left and right mentalis muscle bellies. Relaxing the mentalis will not erase a deep skeletal cleft; filling the structural deficit with a dermal filler or fat graft is necessary.
• Witch's Chin (Chin Ptosis): Characterized by a drooping, sagging chin pad that hangs below the lower border of the mandible, often accompanied by a deep submental crease. This is caused by gravity, loss of mandibular bone volume, and laxity of the retaining ligaments. Neurotoxin will not lift a ptotic chin pad and can exacerbate tissue laxity; surgical submentoplasty, chin implant, or soft-tissue suspension is required.

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Is Mentalis Botox FDA-Approved? What the Labels Say

Every vial of botulinum neurotoxin type A sold in the United States includes an FDA-approved prescribing package insert. While patients frequently assume that any common cosmetic injection is FDA-approved, the regulatory status of the mentalis is unambiguous.

An exhaustive scan of all ten current United States neurotoxin label records — covering every marketed botulinum toxin product — confirms: 0 of 10 labels list the mentalis muscle, chin dimpling, or pebble chin in any indication.

Understanding Off-Label Aesthetic Injections

Off-label prescribing is a legal, routine, and standard part of medical practice in the United States. Once a drug is approved for one indication (such as frown lines), a licensed physician has the legal discretion to prescribe and administer it for other anatomical areas based on clinical judgment and peer-reviewed literature.

However, off-label status carries practical consequences:

1. Manufacturer Constraints: Pharmaceutical companies cannot market, advertise, or provide official dosing guidelines for chin injections.
2. Informed Consent Requirement: Ethical providers must disclose that the treatment is off-label during your pre-treatment consultation.
3. Variable Technique: Without a standardized, FDA-cleared protocol, injection techniques, dilution ratios, and unit dosing vary widely across clinical practices.

To see how off-label neurotoxin use is structured across the entire face, consult our comprehensive Off-Label Aesthetic Injections Guide.

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What the Clinical Evidence Shows: The Published Data

Despite the ubiquity of chin Botox in aesthetic clinics, the formal clinical trial literature specifically isolating the mentalis is surprisingly lean.

┌────────────────────────────────────────────────────────────────────────────┐
│                    MENTALIS NEUROTOXIN EVIDENCE BASE                       │
├────────────────────────┬───────────────────────────────────────────────────┤
│ LEVEL 1: Placebo RCT   │ • 1 Trial (Beer et al., 2005; n=20)               │
│                        │ • Double-blind, split-chin (toxin vs saline)      │
│                        │ • Statistically significant resting/dynamic cure  │
├────────────────────────┼───────────────────────────────────────────────────┤
│ LEVEL 2: Meta-Analyses │ • Mehdizadeh et al. (2026; 38 studies, n=1,903)   │
│                        │ • Lower face = 70.3% of off-label toxin use       │
│                        │ • 94% pooled patient satisfaction across targets  │
├────────────────────────┼───────────────────────────────────────────────────┤
│ LEVEL 3: Cohort Series │ • D'Emilio et al. (2026; n=400 lower-face series) │
│                        │ • Adverse event rate <12% (mild bruising/swelling)│
│                        │ • Hsu & Frankel (2017): Chin projection increase  │
├────────────────────────┼───────────────────────────────────────────────────┤
│ LEVEL 4: Anatomy Maps  │ • Choi et al. (2021; 44 cadaver + 66 US hemifaces)│
│                        │ • Yi et al. (2023; complication mapping)          │
└────────────────────────┴───────────────────────────────────────────────────┘

1. The Anchor Placebo-Controlled Trial (Beer et al., 2005)

The only randomized, double-blind, placebo-controlled study evaluating botulinum toxin for chin rhytids was conducted by Kenneth Beer, Michael Yohn, and Jill Closter in 2005 (published in the Journal of Drugs in Dermatology, PMID 16004014):

• Study Design: 20 adult subjects with moderate-to-severe dynamic chin rhytids received onabotulinumtoxinA (Botox) on one half of the chin and sterile saline (placebo) on the contralateral half.
• Efficacy Results: Physician evaluators and blinded photograph raters identified a statistically significant improvement in rhytid severity on the toxin-treated side compared to the placebo side, both when the chin was at rest and during maximal voluntary mentalis contraction.
• The Satisfaction Split: Patient satisfaction scores revealed an intriguing paradox: 11 subjects were satisfied, 7 were not satisfied, 1 was unsure, and 1 was very unsatisfied.
• The Split-Chin Artifact: The authors attributed the low satisfaction to the split-face design itself: paralyzing only one-half of the chin created noticeable lower-face asymmetry during speech and animation. That interpretation is plausible, but it is the authors' explanation of the satisfaction data, not a separately measured outcome.

2. Large Systematic Review & Meta-Analysis (Mehdizadeh et al., 2026)

A 2026 PRISMA-compliant systematic review and meta-analysis published in the Annals of Plastic Surgery (PMID 41604510) evaluated off-label aesthetic botulinum toxin across 38 studies and 1,903 patients:

• Lower Face Dominance: Lower-face targets (including the mentalis, depressor anguli oris, and masseter) accounted for 70.3% of all off-label aesthetic neurotoxin interventions.
• Satisfaction: Pooled patient satisfaction across off-label lower-face indications was 94% (95% CI: 88%–98%).
• Safety Profile: Serious adverse events were vanishingly rare, with minor transient complications (localized bruising, mild asymmetry) resolving spontaneously.

3. The 400-Patient Long-Term Series (D'Emilio et al., 2026)

A 2026 observational study published in Aesthetic Plastic Surgery (PMID 41261253) tracked 400 patients receiving lower-face neurotoxin rejuvenation over a multi-year follow-up period:

• Adverse Events: Mild, self-limiting adverse events occurred in fewer than 12% of patients, consisting primarily of injection-site bruising, temporary soreness, and transient tightness.
• Cumulative-Effect Hypothesis: Patients received a standardized 120 to 160 units per full-face session every six months. Results persisted longer than the expected pharmacological effect window, which the authors interpret as functional muscle retraining — a hypothesis drawn from a retrospective, single-center series, not a proven cumulative effect, and not a reason to expect dose reductions.

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Anatomy Deep-Dive: Why Placement Errors Cause Smile Asymmetry

The mentalis does not exist in isolation. It sits in an intricate, crowded muscular crossroad where millimeters dictate the difference between a pristine chin and a paralyzed lower lip.

       [ LOWER LIP ]
    ====================
     /   |   ||   |   \
    /    |   ||   |    \
   /    [DLI]||  [DLI]  \     <-- Depressor Labii Inferioris (Lip Eversion/Depression)
  /          ||          \
 /        [MENTALIS]      \
/       /    ||    \       \  <-- Paired Mentalis Bellies (Central Dome)
|     [DAO]  ||   [DAO]    |  <-- Depressor Anguli Oris (Pulls Mouth Corners Down)
\            ||            /
 \           ||           /
  \______[MANDIBLE]______/

Cadaveric & Ultrasonographic Dimensions (Choi et al., 2021)

A landmark anatomical study by Choi and colleagues (Toxins, PMID 33514053; PMC7911364) examined 44 adult cadaveric hemifaces and 66 ultrasound-mapped hemifaces to establish precise spatial coordinates for the mentalis:

• Distance from Midline: The main muscle belly is concentrated 5 to 10 mm lateral to the midsagittal midline.
• Distance from Mouth Corner: The bulk of the muscle lies 20 to 30 mm below a horizontal line connecting the cheilions (corners of the mouth).
• Depth from Skin: The mean target injection depth is 6.7 mm to 10.7 mm beneath the epidermis, situated directly on the periosteum of the mandibular bone.
• Morphology: In 86.4% of hemifaces, the mentalis forms a unified, dome-shaped muscular apex (Type A), while 13.6% exhibit a separated, bifid muscular configuration (Type B).

The Danger Zones: Neighboring Musculature

Yi and colleagues (Anatomy & Cell Biology, 2023, PMID 36796830; PMC10520866) highlighted that virtually all lower-lip motor complications stem from injector unfamiliarity with three anatomical boundaries:

1. The Depressor Labii Inferioris (DLI) Danger Zone (Lateral Drift):

   • The DLI originates from the mandible just lateral to the mentalis and travels upward to insert into the lower lip. Its function is to pull the lower lip downward and outward when smiling or speaking.
   • If an injector places the needle more than 10–12 mm away from the midline, or uses excessive volume that diffuses laterally, toxin paralyzes the DLI.
   • The Result: The affected side of the lower lip cannot pull downward during a broad smile. The unparalyzed side moves normally while the paralyzed side remains stuck upward, creating a noticeably uneven smile that patients sometimes mistake for a stroke or Bell's palsy.

2. The Orbicularis Oris Danger Zone (Superior Drift):

   • The circular sphincter muscle of the mouth encircles the lips. The mentalis interlaces with the lower border of the orbicularis oris near the labiomental crease.
   • If toxin is injected too superficially or too high (above the prominence of the chin), it diffuses into the lower lip sphincter.
   • The Result: Loss of oral competence. Patients experience difficulty drinking through a straw, rinsing their mouth without leaking water, pronouncing "B" and "P" sounds, or playing wind instruments.

3. Paradoxical Mentalis Bulging (Yu et al., 2020):

   • Documented in the Journal of Cosmetic Dermatology (PMID 32346978) in a 26-year-old patient treated for cobblestone chin, paradoxical bulging appeared two days after an otherwise routine mentalis injection.
   • The Mechanism: The authors attribute it to imbalanced relaxation — uneven diffusion leaves some muscle fibers paralyzed while neighboring fibers stay hyperactive, producing a focal, unnatural lump on the chin during animation. In the reported case, an ultrasound-guided touch-up dose into the remaining hyperactive fibers resolved it; the authors' conclusion is that injection should cover the full thickness of the muscle.

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Unit Dosing, Longevity, and Procedure Cost

Because every patient's muscle mass, baseline tone, and facial dimensions differ, there is no universal dose for pebble chin Botox. Dosing must always be customized by an experienced injector.

Typical Unit Ranges

In published clinical series and expert consensus panels, typical doses for isolated mentalis treatment fall into the following ranges:

• OnabotulinumtoxinA (Botox) / IncobotulinumtoxinA (Xeomin) / PrabotulinumtoxinA (Jeuveau): 4 to 8 total units (divided into 1 midline point or 2 symmetric points 5 mm on either side of the midline).
• AbobotulinumtoxinA (Dysport): 10 to 20 total units (accounting for Dysport's ~2.5:1 unit conversion ratio).
• DaxibotulinumtoxinA (Daxxify): 8 to 16 total units (accounting for Daxxify's 2:1 nominal unit ratio).

Clinical Guardrail: Conservative injectors almost always start at the lower end of the dosing spectrum (4 to 6 Botox units). Because the mentalis is a small muscle, under-treating is easily corrected with a two-week touch-up, whereas over-treating or causing lip ptosis cannot be reversed and must be endured for months.

Treatment Longevity

• Onset: Initial softening begins within 3 to 7 days post-injection.
• Peak Effect: Full muscular relaxation and skin smoothing are achieved at 10 to 14 days.
• Duration: Because the lower face is in constant motion during eating, speaking, and swallowing, lower-face toxin wears off slightly faster than upper-face injections. Most patients experience smooth results for 10 to 14 weeks (2.5 to 3.5 months) before dynamic dimpling gradually returns.

Cost Breakdown

Aesthetic practices price mentalis injections through one of two models:

1. Per-Unit Pricing: Most dermatologists and plastic surgeons charge between $12 and $25 per unit of Botox. A 6-unit treatment at $15/unit equals $90.
2. Per-Area or Minimum Treatment Fee: Many high-end practices institute a minimum office procedure fee (typically $150 to $300), or bundle chin toxin with adjacent areas such as the DAO for downturned mouth corners or the lip flip.
3. National Benchmark: The American Society of Plastic Surgeons (ASPS) 2023 Procedural Statistics Report benchmarks the average physician fee for botulinum toxin at $697 per treatment session — a member-surgeon average across all anatomical sites, not a mentalis-specific price. Isolated small-area injections in outpatient clinics typically range between $100 and $250.

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The Projection Paradox: How Chin Botox Can Improve Your Profile

One of the most fascinating findings in facial plastic surgery is that relaxing the mentalis can visibly alter the perceived forward projection of the chin without adding a single droplet of filler.

HYPERACTIVE MENTALIS (Pre-Treatment)        RELAXED MENTALIS (Post-Toxin)
         [LOWER LIP]                                 [LOWER LIP]
              │                                           │
         (----│  <-- Deep Labiomental Crease        (----│  <-- Softened Crease
              │                                           │
          (===)  <-- Bunched Upward / Blunted         (=======)  <-- Smooth, Extended
             /        Chin Projection                    /        Forward Projection
            /                                           /

The Hsu & Frankel Findings (2017)

In a landmark clinical series published in JAMA Facial Plastic Surgery (PMID 28750118), facial plastic surgeons Andrew Hsu and Andrew Frankel analyzed patients with hyperactive mentalis muscles who presented with apparent chin weakness (microgenia):

• The Pathophysiology: When the mentalis is chronically hyperactive, it contracts in a cephalic (upward) direction. This pulls the soft-tissue chin pad upward toward the lower lip, deepening the labiomental crease and blunting the forward projection of the chin.
• The Toxin Effect: Injecting onabotulinumtoxinA into the mentalis relaxes this upward pull. The soft tissue pad settles downward and slightly forward into its natural anatomical resting position.
• The Outcome: In patients with mild retrognathia caused by muscular bunching, toxin alone restored a balanced, elegant profile, softening an exaggerated labiomental groove and extending the vertical length of the lower face.

When Toxin Is Not Enough: Filler vs. Implants vs. Genioplasty

While Botox can release a bunched chin pad, it cannot create bone where none exists.

For patients considering structural volume enhancement for their lower jaw, review our clinical guide to Jawline Filler Principles and the surgical breakdown of Chin Implant Complications and Safety.

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The Complication Map: What Can Go Wrong and How to Manage It

While serious systemic complications from small-dose mentalis injections are exceptionally rare, localized motor complications can significantly disrupt daily life.

┌────────────────────────────────────────────────────────────────────────────┐
│                    MENTALIS BOTOX COMPLICATIONS MATRIX                     │
├───────────────────────┬──────────────────────┬─────────────────────────────┤
│ Complication          │ Anatomical Cause     │ Clinical Presentation       │
├───────────────────────┼──────────────────────┼─────────────────────────────┤
│ Lower Lip Ptosis      │ Lateral spread into  │ Paralyzed lower lip; cannot │
│ (Smile Asymmetry)     │ Depressor Labii Inf. │ pull lip down when smiling  │
├───────────────────────┼──────────────────────┼─────────────────────────────┤
│ Oral Incontinence     │ Superior spread into │ Inability to seal lips;     │
│ (Drooling / Slurring) │ Orbicularis Oris     │ drooling; impaired plosives │
├───────────────────────┼──────────────────────┼─────────────────────────────┤
│ Paradoxical Bulging   │ Superficial partial  │ Focal lumping/nodule during │
│ (Focal Chin Lump)     │ block; deep spasm    │ animation                   │
├───────────────────────┼──────────────────────┼─────────────────────────────┤
│ Injection Bruising    │ Puncture of mental   │ Self-limiting purple mark;  │
│                       │ vessels / capillaries│ resolves in 5–10 days       │
└───────────────────────┴──────────────────────┴─────────────────────────────┘

1. Lower Lip Ptosis (Smile Asymmetry)

• Why It Happens: The needle was inserted too far laterally (greater than 10 mm off-center), or excessive dilution volume migrated into the Depressor Labii Inferioris (DLI).
• The Impact: When you laugh or smile widely, the normal side of your lower lip retracts downward to display your lower teeth, but the affected side remains stationary or elevated.
• Management: There is no pharmaceutical antidote to reverse botulinum toxin once it has entered the neuromuscular junction. The paralysis will gradually attenuate as new nerve terminals sprout, typically improving within 4 to 8 weeks. In select cases, an expert injector can place a microscopic micro-dose (0.5 to 1 unit) into the contralateral DLI to restore symmetrical lower lip movement, though this temporarily weakens the entire lower lip.

2. Oral Incontinence and Speech Articulation Deficits

• Why It Happens: Toxin diffused superiorly into the lower fibers of the Orbicularis Oris.
• The Impact: Inability to create an airtight lip seal. Liquid may escape from the mouth when drinking, eating soup becomes messy, and pronouncing words with "P", "B", or "M" sounds sounds slurred.
• Management: Supportive care until the toxin naturally degrades. Patients must drink slowly, avoid open cups, and avoid using straws.

3. Bruising and Hematoma

• Why It Happens: The chin is highly vascularized, supplied by the mental artery and submental artery branches emerging from the mental foramen.
• The Impact: A minor bruise at the injection point.
• Management: Apply light pressure and ice immediately after injection. Avoid non-steroidal anti-inflammatory drugs (ibuprofen, aspirin), high-dose vitamin E, fish oil, and alcohol for 24–48 hours prior to treatment to minimize bleeding risk.

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What to Ask Your Provider Before Agreeing to Chin Toxin

Because the mentalis requires meticulous anatomical placement, choosing a qualified, credentialed medical injector—such as a board-certified dermatologist, plastic surgeon, or trained nurse injector under direct physician supervision—is essential.

During your consultation, ask the following diagnostic questions:

1. "Is my chin dimpling purely dynamic, or do I have a static skeletal cleft?" Why to ask: A trustworthy provider will examine your chin both at rest and during animation. If they promise that Botox will erase a deep, permanent central cleft without filler, seek a second opinion.
2. "Where exactly will you place the injection points?" Why to ask: The provider should point directly to the central, lower portion of the chin pad, within 5 to 10 mm of the vertical midline and well below the labiomental crease, demonstrating their awareness of the DLI danger zone.
3. "What dose do you recommend starting with?" Why to ask: Look for a conservative starting dose (typically 4 to 6 units of Botox/Xeomin). A provider who proposes 15 to 20 units into the mentalis on your first visit is over-dosing and dramatically increasing your risk of lip paralysis.
4. "What is your protocol if I experience smile asymmetry or paradoxical bulging?" Why to ask: A seasoned injector will have a clear, structured follow-up policy, offering complimentary evaluation at 2 weeks and appropriate corrective touch-ups if deep fibers were missed.

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Frequently Asked Questions (FAQ)

How many units of Botox does a pebble chin usually need?

Most patients achieve complete smoothing with 4 to 8 units of onabotulinumtoxinA (Botox), incobotulinumtoxinA (Xeomin), or prabotulinumtoxinA (Jeuveau), or 10 to 20 units of abobotulinumtoxinA (Dysport). Dosing is split into either a single deep midline bolus or two symmetric points placed 5 mm lateral to the midline. Dosages should always be tailored to individual muscle strength and lower face anatomy.

Will my chin go back to normal after the Botox wears off?

Yes. Botulinum toxin binding is temporary. Over 10 to 14 weeks, your motor nerves regenerate new terminal axons and restore normal communication with the mentalis muscle. As muscle tone returns, your baseline chin movement and dimpling will gradually reappear exactly as they were before treatment. Long-term observational series indicate that repeated treatments do not cause muscle wasting or skin sagging.

Can chin Botox make my chin look longer or more projected?

In select patients, yes. If you have an overactive mentalis that constantly pulls the chin soft-tissue pad upward toward your lower lip, relaxing the muscle allows the tissue to settle downward and forward. As documented by Hsu and Frankel (2017), this can visually elongate a compacted lower face, soften a deep labiomental crease, and enhance apparent profile projection without filler.

Why does my smile look crooked or unnatural after chin Botox?

If your smile appears uneven after chin Botox, the toxin has likely diffused laterally into the depressor labii inferioris (DLI) muscle. This prevents the lower lip on the affected side from pulling downward when you smile. While alarming, this is temporary and typically resolves over 4 to 8 weeks as toxin strength fades. Contact your injector for an evaluation.

Can I combine chin Botox with chin filler in the same appointment?

Yes. Combining mentalis Botox with hyaluronic acid chin filler is a gold-standard approach in aesthetic rejuvenation. Toxin smooths the superficial dynamic orange-peel texture, while dermal filler placed deep on the periosteum projects the chin, sharpens the jawline, and fills static volume deficits. Relaxing the hyperactive mentalis can also extend the longevity of the overlying filler by reducing mechanical squeezing forces.

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Sources

1. DailyMed / FDA Prescribing Information: Allergan. BOTOX COSMETIC (onabotulinumtoxinA) for injection, for intramuscular use. U.S. National Library of Medicine, DailyMed SPL. https://dailymed.nlm.nih.gov/dailymed/dailymedDrugInfo.cfm?setid=485d9b71-6881-42c5-a620-a4360c7192ab
2. DailyMed / FDA Prescribing Information: Merz Pharmaceuticals. XEOMIN (incobotulinumtoxinA) for injection, for intramuscular use. U.S. National Library of Medicine, DailyMed SPL. https://dailymed.nlm.nih.gov/dailymed/dailymedDrugInfo.cfm?setid=3f35d6e0-3450-4abc-a0da-cc7b277e7c6e
3. Beer K, Yohn M, Closter J. A double-blinded, placebo-controlled study of Botox for the treatment of subjects with chin rhytids. J Drugs Dermatol. 2005;4(4):417-422. https://pubmed.ncbi.nlm.nih.gov/16004014/
4. Choi DY, Bae H, Bae JH, et al. Effective Locations for Injecting Botulinum Toxin into the Mentalis Muscle; Cadaveric and Ultrasonographic Study. Toxins (Basel). 2021;13(2):96. Published 2021 Jan 27. doi:10.3390/toxins13020096. https://pmc.ncbi.nlm.nih.gov/articles/PMC7911364/
5. Yi KH, Lee JH, Hu HW, et al. Novel anatomical guidelines for botulinum neurotoxin injection in the mentalis muscle: a review. Anat Cell Biol. 2023;56(3):293-298. doi:10.5115/acb.22.266. https://pmc.ncbi.nlm.nih.gov/articles/PMC10520866/
6. Mehdizadeh M, Shariati K, Cordero JJ, et al. Beyond Wrinkles: A Systematic Review and Meta-analysis of Off-Label Aesthetic Uses of Botulinum Neurotoxin. Ann Plast Surg. 2026;96(4S Suppl 4):S124-S133. doi:10.1097/SAP.0000000000004662. https://pubmed.ncbi.nlm.nih.gov/41604510/
7. D'Emilio R, Caputo MG, Rosati G, et al. The Long-Term Efficacy of Botulinum Toxin Type A for Lower Facial Rejuvenation in 400 Patients. Aesthetic Plast Surg. 2026;50(5):1960-1968. doi:10.1007/s00266-025-05317-6. https://pubmed.ncbi.nlm.nih.gov/41261253/
8. Hsu AK, Frankel AS. Modification of Chin Projection and Aesthetics With OnabotulinumtoxinA Injection. JAMA Facial Plast Surg. 2017;19(6):522-527. doi:10.1001/jamafacial.2017.0606. https://pubmed.ncbi.nlm.nih.gov/28750118/
9. Yu N, Liu Y, Chen C, et al. Paradoxical bulging of mentalis after botulinum toxin type A injection. J Cosmet Dermatol. 2020;19(6):1290-1293. doi:10.1111/jocd.13437. https://pubmed.ncbi.nlm.nih.gov/32346978/
10. American Society of Plastic Surgeons (ASPS): Botulinum Toxin Procedure & Cost Reference. https://www.plasticsurgery.org/cosmetic-procedures/botulinum-toxin