Hes about 8 or nine months I thought maybe it was coloring but it is not on both sides and I have not had to force his mouth open. I fed him hornworms the other day and he did have a little bit of a struggle to rip one off the piece of wood it was holding on to. I thought maybe could link it to that but he hasn't wanted to eat since then either an his colors been off. Maybe the horns shook him up? Guess Ill just keep a close eye on him. Thanks for the input!
Is he in a black screen cage? If so, then he might have been rubbing against it. My Cham had the exact same thing on his mouth. He was trying to get some shedding off by using to walls of the cage, and his lips were black afterwards.
It looks like bruising to me. I wouldnt be worried about it just yet. If there is an issue inside the mouth, then I would worry. Try to get a good look inside, and see how it looks.