I can tell you this much, I am 100% certain that they were stress scars. I have seen photos of these scars, and I saw them on my cham. They could never be burn marks because he was nowhere near a light wich he could get closer to. I know this because I did plenty of research not only on the web, but in libraries all over city. My cham doesnt have a tail, and at first (before he gained more strenght in his hands) he would fall, but never physically injure himself. (I always double checked) These black spots slowly developed and were just that spots. Even the exotic species vet said that he didnt know what they were. Told me that it could be internal virii. It was nothing as such.
And also this was not unshed skin that had been builing up on his body. (I was suggested that too) Chameleons scar on their bodies from time to time. Sometimes you notice it, and some you dont. But dont treat is as a burn. They look completely different.