Botox of the masseter muscles causes the muscles to atrophy or shrinken. This process takes months and repeat treatments to improve and thin the lower face. Patience is key; immediate results are not expected. -Dr. Keaney
Patients seem to have a misconception about injecting botox into the master muscle. It is not a one time procedure. This has to be repeated several times over a year or more period to see the flattening of the muscle.