Last year I had Botox injections (4 in total) to my left masseter to treat hypertrophy. This worked well in reducing the muscle bulk but the last injection 5 months ago also caused considerable volume loss to my left cheek. Volume has returned but not as full as before. What is really concerning me is that I have recently developed a jowl on this side of my face which I did not have before. I am scared this is permanent. Will this disappear in time? Will using a facial exerciser help? I am 52.