@melancholykiddo I don't see anything on his skin but I do see incredibly deeply sunken eyes. Having worked with a lot of chameleons in severe pain, his "vibrating" is not likely an indication that he is in pain. That has not been the kind of response I've seen to pain. Chameleons are not mammals and don't respond the same way.
You really need to look at his hydration levels because his eyes really shouldn't look like that. Granted, some chameleons will pull their eyes in when you take pictures of them, but you didn't mention it.