Hey Jessica, sometimes they just need extra time to settle in. Not hiding is a sign of stress and he just might be a little freaked out.
A trick for "sensitive" snakes that I've found to be pretty effective is to literally fill the bottom of the cage with balled up newspaper sheets. I know it sounds a little unorthodox but it works - it basically forces them into feeling much more secure, regardless of whether or not they choose to use the hides that you provided. Over the course of the following weeks, you gradually remove the paper until the tank is clear and the snake is settled in.
Also make sure that the tank isn't in any high-traffic areas, loud music, etc. I was once helping a guy out with a snake that wouldn't eat and after exploring EVERY point of failure with the setup plus a trip to the vet, I found out that the tank was set up in the living room sitting right next to the subwoofer of a home theatre system. HELLO?!