Your first mistake was handling him only a few days after getting him. He was probably a bit freaked out by the move. He was probably even more freaked out if you kept changing his setup. Each change you make to a setup can cause stress for the snake.

The second mistake was not yours but of the previous owners. Ball pythons should eat more often than once a month. The strike + coil leads me to believe that he is underfed and is just really really hungry.

Try giving him a small rat in one week. For that week, do not handle him. Wait 2 days after feeding him (you should always practice this) before attempting to handle him. The best time to handle them is when they are hiding. That means they feel safe and secure. Roaming is generally either stress or hunger. Neither would be a good time to handle your snake.

Make sure he has two identical tight fitting hides. Not half logs.