Jean/MVP
I don't remember much about coming back. I think my situation was a little different than yours. I know that I died and would have stayed that way if not for intervention from...well, you remember graduation, right? That thing. She kind of used me as a meat puppet as a vessel for the weeks following the cave accident.
I was able to shake off her control when she went crazy at graduation.
As for what happens in between...I remember a bright white place.