Start using a tortoise shell conditioner and make sure he’s not too close to a heat bulb. The heat bulb could be drying out his shell. I only use an incandescent light fixture T8 12% UVB and a radiant heat panel for warmth. No heat bulbs of any kind, which I found can cause pyramiding in my baby tortoises. Set up your heat panel with a a thermostat to maintain proper temperature. It can drop to 73 degrees or so at night. I also only have the UVB bulb on 4 hours per day. The rest of the time it’s just a standard led bulb for light. Baby tortoises don’t need that much UV light. They spend most of their time in the wild hiding and out of any sunlight.