How long does it take for masseter Botox to work?

The first time injection of Botox will soften the masseter muscle but will not necessarily reduce it in its size.  As you keep repeating it over years eventually the size of the muscle will reduce from atrophy of the muscle.Even after the first time you will see some improvement within 2-3 months.RegardsDr. J

Unlike regular wrinkle injections, the effect of injections in the masseters takes about 4-6 weeks before you see the difference and typically last between 4-6months before needing another treatment.