I don't know, Hot Rod. I'm prone to believing explanations that have been around longer than the movie, and I've always heard that his manipulation of the dark side manipulated him back. And I think the line, "I can't hold it much longer, I'm too weak," gives away that he's about to get his ass kicked. In a situation like that, I don't think his face lift fading would be the first thing on his mind. Plus, he's trying to get Anakin to step in for him and act bad, and saying that he's about to die would work more effectively than, "I'm not pretty anymore, Anakin! Stop him!"