I've inherited a 13-year-old Ball Python, Jake, and have just fed him for the 2nd time. When I put him in a bin with the rat, he got so excited. But, he missed the rat but, Jake bit himself in the side. For several minutes, he kept biting his own side. Is this normal? I can't see any wounds on him, I didn't see anything ooze from his side. What should I do? Help me please...I'm new at this!