My dragon has been working on a bad patch of shed for a month, to a month and a half. I was giving her a bath today to try and help, but noticed a white area beneath where some of the stuck shed was. The pictures are of her immediately out of the bath so it'll have a wet look, but it doesn't seem to hurt her, doesn't stop her from eating, and she let me brush against it with no complaint. The dark brown spots are just her current stuck shed, doubled over and dark on top of one another since she's fresh out of the bath.
She eats collared greens, escarole, dubia roaches, hornworms, occasional mealworm (she chews her food) and occasional butterworms once a month as a treat. UVB 10.0 ho and a heat spot between 96-100 depending on the day. Ambient humidity between 30-40. Give her dusted calcium and vitamins regularly.
It appears to possibly be a burn or some sort of fungal growth. Is your dragon able to get close enough to the heat lamp? And what are you measuring your basking surface temp with?
How long has the area been like that? Since the start of the shed a month ago?