Very often, a square jaw, is due to increased strength and volume of the jaw muscle, called the Masseter. This can be reduced with the use of boulinum toxin injections like BOTOX, giving a less square jaw with a softer angle. You will generally notice softening of the masseter muscle at 2 weeks and softening of the jawline over the next 4 weeks.
Researchers have observed that with continued treatment the reduced power of the muscle can actually allow the body to remodel the bone shape, so that your softer jawline is due both to muscle volume reduction and a change in your jaw shape to a more feminine line. The effects can be truly remarkable.
The method for BOTOX injection into the masseter is quick and painless, with no downtime. You may require a second treatment at 4-8 weeks, but generally this is not necessary. The effects of the botulinum toxin in weakening the muscle lasts about 3-4 months, but very often the effects last far longer and many people find they only require a repeat treatment about once or twice a year before the masseter volume begins to increase again.