I believe that they are thermal burns. I have the same thing going on in the same areas. I'm thinking that chameleons must have less nerves in that particular area and can't feel when it gets too hot.
When they are relaxed, you can't see the discoloration, but when they darken up, those areas don't change color.
These photos are of two different chameleons with exactly the same burn pattern BTW. Looks like the exact pattern on your panther although yours is less severe.