If he returns as a Wyatt family member, he should shave his head again. He looks more like a freak that way and that would only look appropriate for him if he's gonna belong to their ilk. (He should be bald again in real life anyway, from shooting See No Evil 2.)
I can't really see this happening, though. Kane might tease being 'one of them' for awhile, but he'll quickly turn on them if he does. Or the Undertaker will return and cause him to snap out of it, setting up a handicap match between the Brothers Of Destruction and the Wyatt Family at Survivor Series.