What is the Correct Way to Inject Botox for Jaw/masseter Contouring?

Some people develop large lower cheek girth from their chewing muscles (masseter) enlarging from clenching or grinding their teeth. Sometimes this is related to TMJ syndrome in which the joint of the jaw movement hurts. It is important to treat the muscles symmetrically so there is no imbalance that could exacerbate the TMJ. Injections need to be deep enough to affect the muscles. the enlargement will take time to diminish, even if the Botox was effective in relaxing the masseter muscle activity.

Your masseter muscles are deep and easily detected prior to and during injections. If your provider has said it takes two weeks to show visible slimming, I'd question that. Without seeing you in person, it's difficult to know how many units per side you'd need, but 20 units per side is a small amount for masseter reduction. Size reduction takes a fairly large amount of product. Results take several months to show, and the treatment is on-going.