The photo is small enough that I can't really get a good look. I've never dealt with anything quite like that - no white patches that weren't related to shedding. If you're quite sure it's not that, and that it can't be a burn, I'd recommend a vet visit to see if it's a fungus.
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Torey
Eugene, Oregon, USA
1.2 Saharan Uros (Joe, Arthur, and Hitch)
3.0 Mali Uros (Spike, Turtle, and Tank)
1.1 Ornate Uros (Scuttlebutt and Shazzbot)
1.2 Collared Lizards (Ripcord, Thiamine, and Riboflavin)
1.0 Green Anoles (Sprocket)
1.1 Housecats (Roscolux and Jenny)