First double and triple check your humidity and temperatures. Make sure you have 2 hides, one on the hot side, the other on the cool side.
Aside from that you typically shouldn't worry about a finicky eater (which is normal for ball pythons) unless it's loosing weight. Also don't handle him aside from routine maintenance until he's eating better for you because it could be stress related. Depending on the age the roaming and lack of eating could be a breeding thing.