posterior fossa/ muscle wastage

I got bells palsy when I was 13 of age. I was put on steroids and instructed to do physio for 2 weeks. I only did 2 days physio but a couple weeks later everything seemed resolved. I had what appeared to be a complete recovery. A couple yrs on my facial muscles became weak, smiling.laughingwhistling all became difficult, but there was consisent facial weight loss from my face. The problems continued and finally a year later I saw a neurologist who said everything was fine. Anyway a year later he reluntantly let me see a physiotherapist who said my neck,chin,cheek muscles were weak and there was a loss of muscle tone. She pointed out it was residual damage from bells palsy. Two things I find strange I was perfectly fine two weeks after bells palsy but there was wastage of muscle on both sides of my face. I got bells palsy on the left side so if there was residual damage rather than the muscle weakness spreading to the right, should this infact of made the right side even stronger? Secondly the hospital did a Brain MRI of me for a different medical problem. This showed the posterior fossa was remarkable as it was quite shallow in appearance and the consultant noted on his medical notes he was a little concerned as this was atypical. I was told there was nothing tumorous in my brain put I researched posterior fossa brain tumor, and saw syptoms (symptoms). I had some of them. A) Inbalance when I walked. B) Tiredness/Drowsiness C) Eye Deviations includign Opsoclonus, Myokymia, Myoclonia, Nystagmus and Diplopia. D) Facial muscle weakness.  My main problem for me was the loss of muscle tone from my face as a healthy full complexion had over the years turned into a very gaunt and thin complexion to my face which was affected on both sides. Could the concern with the posterior fossa have caused the muscle to weaken and thin?