I'm sorry your "baby" and family are dealing with MG. Although back pain does not sound like MG per se, the weak legs could possibly mean MG. In a large percentage of people with ocular MG, generalized MG develops eventually. I hope that isn't what is happening, but I agree with you that the doctor should be notified. With symptoms like she is showing, it could be several different things other than MG as well.

I hope you find some answers soon and your girl starts feeling better!