Well, if Kimimaro lives, perhaps he'll turn into a good guy in around 80 more chapters, like Gaara did.

But then again, no, its only you.

Kimimaro knew from the very begining (when they showed him in a medical bed) that Oro was already having a new body being delivered, and he decided to go get it even if that meant he was going to be discarded. So no, he wont change sides.