Lisa, I'm sorry you are having to deal with MG all over again. I think all of us hope that it will go away and never come back!
When did you start Pred? Was it recently? Don't forget that while on Pred, a "slightly" elevated white count can mean that it's actually much higher. Do you have signs of any kind of infection? Do you know the actual ESR count?
Do you have any other symptoms that might indicate something else going on? Like a new thyroid condition making MG come back? Anything that makes the immune system work harder can make MG worse or bring it back.
I think the hardest part of MG is the fact that none of us can really predict what it will do. And I can't imagine the absolute relief of getting rid of any signs of it and then having to deal with it again. I would LOVE to get rid of my MG - even if it's for a day or two.
It sounds like you have good care. That's half the battle. Hang in there. You can handle this! I know it sucks but you CAN do it.