Masseter Botox is one of the most satisfying treatments when the patient is the right candidate. The key is figuring out whether your 'round face' is actually driven by masseter muscle bulk, or by something else that won't respond to Botox. How to tell if masseter Botox will help you: The bite test: clench your teeth firmly. Feel the muscle bulge that pops out at the back of your jaw (just in front of and below the ear). If that muscle is large or prominent, you have masseter hypertrophy and Botox will reduce it. The pattern: round face from masseter bulk shows widest at the lower jaw area (around the angle of the mandible). Round face from fat shows widest at the cheek or midface area. The teeth-grinding clue: patients who grind teeth at night, clench during the day, or chew tough food often have masseter hypertrophy. If you have any of these history items, you're more likely a good candidate. What masseter Botox does: Injected directly into the muscle (typically 20 to 30 units per side). The muscle gradually atrophies over 4 to 8 weeks. Face becomes narrower at the jawline angle, more tapered toward the chin. Duration: results last 4 to 6 months. Repeat treatments often give longer-lasting effect as the muscle stays smaller between sessions. Bonus benefit: also reduces teeth grinding, jaw clenching, and TMJ pain in many patients. Useful even if cosmetic concern is secondary. When masseter Botox doesn't help: If your round face is from buccal fat fullness (the cheek hollow): masseter Botox doesn't affect this area. If your round face is from cheekbone width or zygomatic bone projection: bone doesn't shrink with Botox. If your round face is from subcutaneous fat overall (especially in younger patients with naturally fuller faces): masseter Botox won't change overall fat distribution. What to expect realistically: In a good candidate, masseter Botox creates 10 to 20 percent facial width reduction at the lower jaw over 2 to 3 months. Subtle but real. Patients commonly say 'my jaw looks more refined' or 'I look slimmer.' It's not a dramatic transformation in most cases — it's a softening. Expect a refined jawline angle, not a complete reshape. What I'd avoid: Heavy first-time dosing (start at 15 to 20 units per side, build up if needed). Combining with buccal fat removal until you've seen what Botox alone does. Treatment without first checking if you actually have masseter bulk (some round faces don't). Best move: see an injector who'll palpate your masseter while you bite down before recommending treatment. If the muscle isn't bulky, they should tell you Botox won't help and discuss other options. If your injector recommends masseter Botox without doing this exam, get a second opinion.