Welcome, welcome!
We'll definitely need some more deets. BPs refusing is almost always due to husbandry. Here are my questions:
- Is the UTH regulated with a thermostat? If so, what is the temperature of the glass reading with IR gun? I see you noted 91 degrees for the warm side, but is this the temperature of the substrate or the glass?
- What is the ambient temperature?
- Does he have two identical hides on both sides?
- Is there enough clutter for him to feel safe?
- Are you feeding live or f/t and what size (also, invest in a cheap food scale from Amazon -- it'll make your life a lot easier)
- How long exactly has it been since he last ate?
These answers will help us!