Clare, It was probably the lidocaine or novocaine or whatever they used that caused you to be weaker. Did you tell your neuro about it? It's a classic MG reaction to nerve blockers/anesthesia. Do you still have some Mestinon or are you one of those MGers who can't tolerate it? It would probably help you right now!
I have the dentist use Xylocaine. For whatever reason, I do better on that one. But, hey, you might not!
I react in a similar way to epinephrine. There's a trick to it! You can sip some juice (apple or whatever) after they give you the shot! It counteracts the effects!! I just bring a little juice box with me.
I'm glad you have been relatively okay! But as this dental appt. proved, there's no such thing as "mild" MG!
Maybe you don't have obvious test results for MG because you're on immunosuppressants!

Were you on Cellecpt when you had the MG tests done?
Limpy, that sounds very scary! It always amazes me how this disease can be triggered by so many things.
Take care you two!
Annie