Can't really call this an "urgent" care issue, as it's been going on for almost a year. I've tried treating it with tea tree oil and antibiotics, and I'm pretty sure it's not rot - but not sure. Is it growth? I thought at one point he was getting too much UVB, but after adjusting the amount of time and distance from the bulb, he still has the issue. When I scratch his shell with my fingernails (which he loves) I get little tiny pieces coming off under my nails. Are the white parts disease, molting or something else?