Botox for masseter? (Photo)

So I'm currently thinking about getting masseter botox. I grind my teeth a lot at night and use nightguards. I have always had pretty wide face. I Have defined jawline and very wide cheekbones. Also a large head. I do have pretty hollow cheeks and if my face gets puffy they are pretty much gone and i look terrible. My temples are pretty wide aswell from bruxism. Can I get botox to slimmer my temples? Can masseter botox slimmer my midface a little also? Does it make my cheeks look bigger? Help!