Masseter Botox Before and After: A Realistic Timeline
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I'm Dr. Jong Seon Kim, a plastic surgeon at Gangnam HERA in Seoul and a board member of the International Petit Medical Society. Masseter botox is the single most requested treatment among international patients who message us before flying in, and almost every message contains the same hidden question: "How fast will my face look slimmer?"
When does masseter botox actually show a change?
The muscle begins to relax at three to seven days, but visible slimming takes weeks. That gap confuses people. Botox stops the muscle from contracting quickly; the bulk itself shrinks only as an unused muscle gradually loses volume. A photograph taken one week after injection usually shows almost nothing β and that is normal, not a failure.
This is the opposite of forehead or frown-line botox, where the change is visible within the first week. Jaw slimming is a volume change, not a wrinkle change.
What a trustworthy before-and-after shows
- An interval stated in weeks, not "after".
- The same angle β a three-quarter view flatters a jawline more than a front view does.
- Relaxed jaw, teeth apart. Clenching changes the outline more than the treatment does.
You can see case records from treatments performed here in our patient case gallery, filterable by treatment.
Who it suits β and who it doesn't
It suits a jaw that looks wide because the masseter muscle is overdeveloped β often from clenching or grinding. Press your back teeth together and feel the muscle bulge at the angle of the jaw; if that bulge is what bothers you, this treatment addresses it.
It does not narrow bone. If your width comes from the mandible itself, botox will not change it and I will say so rather than sell you a series that cannot reach your goal. It also does not lift sagging along the jawline β that is laxity, and belongs to lifting.
What we do in the room
The injection takes about five to ten minutes. I ask you to clench so I can map the muscle border, then place product inside that border β dose follows the muscle I can feel, not a fixed menu. At HERA botox is physician-injected and we follow a genuine-product protocol with opening, serial and record handling.
Downtime is minimal. Tiny needle marks or slight redness may appear briefly; avoid rubbing the area afterwards.
What patients ask me next
"Will my face look gaunt?"
Not at a conservative dose. Over-treatment is what hollows the lower face, and it is the error I actively avoid β I would rather place less and review you than overshoot a muscle you use to chew.
"Does chewing get weaker?"
Some patients notice mild fatigue with hard foods in the first weeks. It settles as the dose wears down.
"How often will I need it?"
Effects generally last about three to four months and vary by individual. Repeated treatment is what keeps a slimmer line, and intervals often lengthen once the muscle has been relaxed for a while.
Why your photograph and your mirror disagree
Patients often tell me the mirror looks unchanged while friends say their face looks slimmer. That is not imagination. You see your face daily and adapt to gradual change; a friend who saw you two months ago does not. It is also why I ask patients to photograph themselves at a fixed angle before the first session β memory is a poor baseline for a change that arrives over weeks.
Take the photo in daylight, from the front and from a three-quarter angle, teeth apart and jaw relaxed. Repeat it at four weeks and eight weeks. Those three frames will tell you more than any clinic's gallery.
What a second round changes
The first round relaxes a muscle that has been working hard for years. The second round, placed before the muscle has fully recovered, usually produces a cleaner line than the first β which is why patients who judge the treatment on a single session often undersell it to themselves.
The honest limits
It is maintained, not permanent. Results vary between people because muscle size and strength differ β the same units in two faces do not produce the same photograph. And if grinding is driving the bulk, treating the muscle without addressing the habit means the bulk returns faster.
The clinical detail β who it suits, how a session runs, recovery and the honest limits β is set out on our Allergan Botox page.
Book a consultation
If you would like me to assess your jaw, send us a message. We will arrange a consultation in Gangnam, or a photo consultation first if you are still abroad. An English interpreter joins every visit, and you receive an itemised written estimate before anything begins β international and local patients pay exactly the same.
FAQ
Frequently asked questions
Q1When will I see masseter botox results?
The muscle relaxes at three to seven days, but visible jaw slimming takes weeks because the bulk shrinks gradually as the muscle goes unused. A photo taken one week after injection usually shows very little, and that is normal.Q2How long does masseter botox last?
Effects generally last about three to four months and vary by individual. Intervals often lengthen once the muscle has been relaxed for a while.Q3Will masseter botox make my face look gaunt?
Not at a conservative dose. Hollowing of the lower face comes from over-treatment. I would rather place less and review you than overshoot a muscle you use to chew.Q4Can it narrow a wide jawbone?
No. Botox reduces muscle bulk, not bone. If your width comes from the mandible itself, I will tell you at the consultation rather than sell you a series that cannot reach your goal.Q5Does chewing become weaker?
Some patients notice mild fatigue with hard foods during the first weeks. It settles as the dose wears down.
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A Medical Team That Sees You Through, Start to Finish
Board-certified specialists who treat every patient like family β the same doctor guides you from your first consultation to your final result, aiming for natural beauty with minimal need for revision.
Jong Seon Kim, MD
βI am a doctor you can trust, dedicated to enhancing your natural beauty.β
Career & Credentials
- Director, Gangnam HERA Plastic Surgery Clinic
- Board Member, Korean Society of Aesthetic Surgery (KSAS)
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Dr. Lee Jong Hoon
βI dedicate myself to achieving the best results with minimal need for revision.β
Career & Credentials
- Co-author, LIFTINGOLOGY: Science and Clinical Practice in Aesthetic Medicine
- Recipient, Minister of Health and Welfare Award for Outstanding Contribution to National Health Improvement
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