IDK if it's natural growth or a transplant, but he had the same hair style after the show was cancelled. I guess he wanted to keep it, but had to shave his head again for all the flashback stuff since they don't film in order, so probably used the time away as a chance to grow it back.
I think the Vic thing is the way the are going to break Jane and Mike up. Likely because she'll want to care for him during his dying days. Let's face it the long distance storyline can't go on for long.