Mestinon - Hey, about 1,5 years ago I started having double vision and drooping lids After all tests

... came... back negative the docs concluded it was occular MG. After taking mestinon on a fairly high dose (10pills in a day) with no effect I was told to stop it (but not specifically to taper off it). Anyway I was misdiagnosed because I ended up doing absolutely nothing after a prednisone treatment of 4months and it pretty much fixed itself. I've recently been able to go back to the gym so here's my issue:
When I first took that mestinon dose the day after I took 10pills and was told to stop it and took none I went to the gym where I realised I had severe muscle weakness in especially the triceps (perhaps also the pectorals, the groups I was focusing on that day). At the time the docs said it was part of the MG. but now a year later I still have a noticeable weakness in those muscles... I feel as if they are not responding properly... Kind of like paralysis... Specifically the lateral head of the triceps... Any help? I was told creatine might help... or just be patient and keep working them ? Any ideas