Myasthenia Gravis Support Group
Myasthenia gravis (MG) is a neuromuscular disease leading to fluctuating muscle weakness and fatiguability. The hallmark of myasthenia gravis is muscle weakness that increases during periods of activity and improves after periods of rest. Although myasthenia gravis may affect any voluntary muscle, muscles that control eye and eyelid movement, facial expression, and...

Be aware of the medications that could cause MG to flare. Lidocaine being one that most dentists use. My dentist uses carbocain on me. It's short acting, so he know I might need another shot before he us done. You can find a list of medications to avoid on the previously mentioned web sites.
I have had to cancel many appointment and social activities because I was having a bad day. MG will get better with the right treatment. Learning to say NO (without guilt) is the best thing you can do for yourself right now besides resting and not over doing. I have a constant struggle with what I want to do and what I know I can do. Good luck to you!
My Dentist knows well to keep that suction-thingy close at hand, as the Mestinon has made me quite a spitter.
Take Care!
My guess is that the same reasoning could be used for someone with MG who is being treated with an immune lowering medication. I would be more worried about the introduction of an infection than getting a weak jaw or MG problem during the process. You can always opt out of the procedure midway if it is a problem. You can ask the the hygienist to be less "thorough" in the procedure too.
Then to be proactive, get something like a water pic to do your own cleaning daily cleaning with a tool that doesn't break the skin and makes the cleaning at the dental office less likely to be so invasive.
Part of the problem we have is the anticipation of problems and the stress that creates. I like to wait until the problem occurs before getting bothered or worrying.
Good Luck
After my crisis my hairdresser picked me up at my house.
Maybe you could find a hair dresser that does walk ins.
Maybe a Monday am would be good for your hair too. At least with hair if you got to the appointment it is restful.
I hope they find something to manage your MG better fast but in the meantime I would focus on resting before hand. Also for your hair appointments, maybe you can find a friend you trust or someone you know that does hair and can make a housecall and understands your situation better. I know there are some people that are happy to help with that if they can, check at church. I hope that helps. Take care.
The first two appointments on Mestinon were much improved. I am getting worse now and could tell at my last appointmet. I always book with the same hygenist who knows my difficulties well. She cleans me in a more upright position. It is harder on her back but she's seen me have coughing/choking attacks before. She often skips the salty spray if I'm getting weak and goes with the manual scrubbing. I always take my Mestinon about 30 minutes before the appointment. I normally have dry mouth so the extra spit from Mestinon has made my oral issues less extreme.
Flutebell