What is better for jaw reduction - Botox or jaw shaving?

Botox just addresses muscle bulk, so if a large masseter (chewing) muscle is why your jaw is wide it can make a nice difference.  Is some patients, though, the jaw bone itself is much more prominent than the muscle and botox does very little for these patients.  The other downside to botox is that you have to redo it every few months.  During V-line surgery the bone is removed and most surgeons will also physically remove some of the masseter muscle.  It costs more than one treatment of botox and your jaw is swollen for several weeks, but after that resolves you will have a more significant and permanent change.  In the hands of an experience surgeon or injector both procedures are very safe.  So V-line surgery will produce a much bigger change in the end, but you have higher upfront investment in recovery and cost.  -Dr. Rolfes

Masseter Reduction is where the lower muscle of the face, termed the masseter muscle, is reduced. The benefits of this can be two fold. First of all, patients can improve facial balance and change the shape of an overly square face. Second of all, some patients will experience pain and discomfort as a result of an overly large masseter muscle. Botox can help shrink the muscle and both reduce its appearance and lessen the amount of discomfort the muscle exerts on the surrounding tissues.
Regards Anil Shah

If the reason you want a jaw reduction is because of your jaw muscle, you can do it with botox in addition to jaw surgery.  Botox is an appropriate procedure for those who appear to have deep jaws due to excessive masticatory muscle development, or are plump in their faces. The biggest advantage of Botox is that it will get a v-line look without surgery, but if it's not a muscle or flesh problem but a bone problem, it's hard to get a dramatic effect with Botox. No amount of Botox can reduce bone itself. If the case is Jaw surgery, it is divided into various types of facial bone, degree of square jaw joint surgery, condition of facial bones, precise size of prognathism, mouth protrusion, etc., depending on surgery, and precise method of facial jaw joint surgery.  In your case, I recommend you visit a hospital and consult with a specialist to see if the development of the muscles and/or the development of the bones are showing wide jaws