Masseter botox 5 weeks ago, but there is no change in my face shape. Does this mean that my jaw bone is making my face square?

The amount injected seems enough, but in my experience it takes several session for the atrophy (muscle reduction) to take place.  Clench your jaw and feel what the muscle mass feels like.  This should reduce the more sessions you have.  Underlying anatomy can certainly have an impact on this.

72 units of Botox should definitely weaken your masseter muscles. If it’s not the muscles then the boney structures of your face could be involved. I would revisit the provider who treated you for a revaluation.

36 units of Botox to the masseter muscle, assuming to each side, is a respectable amount. If you bite down and do not feel the muscle contracting or moving, then Botox has done its job in paralyzing the muscle. If this is the case, and there is still no change in the contour of the jawline, then the bone structure is the likely underlying culprit.

It's unfortunate that you did not post any before and after photographs. None-the-less, If you feel that your masseter muscle is weaker when you bite but the shape of your face is not changed, that would imply that it is the skeletal structure that controls the shape of your face and not the masseter muscle. Good luck from New York City

Rmpka,Unfortunately, it is difficult to give you an accurate assessment without a picture. Injection of 36 units to the masseter is considered an adequate dose for reduction of the muscle. To determine whether you are seeing flaring of the face due to muscle or bone, I would place your fingers over the area that seems wide and clench with your teeth. Anything felt tensing up while you clench is usually muscle, while anything that feels hard is bone. I would consult again with your injector or an experienced aesthetic surgeon to discuss your desired outcome and possible treatment options.I wish you the best!Hardik Doshi, M.D.

It is unusual that you have not seen a change in your jawline after 72 units of Botox in the masseter muscles.  This is a "healthy" dose that would have an effect on the muscle so you may note that your jaw is not as sore in the morning if you are a "tooth grinder."  It is also possible that you are not yet seeing atrophy of the muscle.  I suggest follow up and photos with your doctor  to evaluate your progress.  All the best to you.  Alexis Parker MD