Yeah, I had thought about it being the live prey, But we never leave him unsupervised. I always just after he constricts it, and when he shifts around to get a better bite on it. The thing is, is that it wasn't like a surface wound, just the scales were affected.
Before I got him, he had only been eating one medium rat a month, and I'm honestly surprised he was in such an okay health when I acquired him from her. He has such a fast strike after I put the rat into his tank that I just feel like he's famished still. When we first got him, I went ahead and gave him a med rat, but just felt that spending 35 minutes on getting it down was just too much, even though he didn't really seem to struggle that much. He now only spends about 15 minutes once he kills it.