By sitting in the corner, he might be trying to feel secure. Are your hides small enough to were he has contact to all the walls and a low roof (the skull might not be likable for him). What kinds of hides do you have?(half logs with two openings won't make him feel secure enough). He might also be trying to stay cool, so do you have a temp gradient going across the tank (I keep mine with the air temp being 80-82 across the whole tank, and the hot spot being 90, it works just fine for him, I have the lights on dimmers). Finally, temp control for that UTH is critical and I would turn it off until you get one, you don't want to burn your BP, temps of 92 and up is to hot.

Also since you just got him/her, it'll be trying to get use to it's environment, don't handle until a week or two goes by it you don't need to (50+ gal tank is pretty excessive for that young of a BP, depending on were you bought yours, it was probably raised in a rack, which is very confined compared to your tank. Maybe try covering 3 of the tank walls with construction paper, so he won't feel like he is being watched all the time. Good luck, any other problems you might have, there are a lot of people here to help.