UTH might be running too hot. Go to Walmart and get a cheap light dimmer(if you can't afford a thermostat) plug the UTH into the light dimmer. Then go to home depot and get an infra thermometer about $25. Check the UTH temp with the heat gun on a regular basis. Hard to see from your pic but when a snake goes into shed it turns dull and milky blue...check his eyes if they are cloudy blue it's shed.