Hi,
I'm not sure if I can be much help. I've had this happened in my upper eyelid. This has occurred off and on. It act upfor days, or just hours. I'm unDX, but many of my doctors feel I do have MS.
I've read on several web pages that this can occur in MS, and it can have something to do with the cranial nerves. Or just like you get muscle fatigue in your arms, legs, etc,..fatigue can happen with MS in your face, or numbness.