1) More water changes. While bettas are known to change color, red wash in fins are sometimes associated with ammonia "burns". Check you water to make sure the ammonia isn't bad, and that he is only coloring up.
2) He's probably bored as heck. Interact with him, change what you put in his tank. Put things around his tank, and make sure it's differnt each day. Try putting things by his tank he has never seen before. This'll keep him interested, and sometimes if something catches his eye, he'll be too busy staring at it to bite his tail. (This did wonders when my betta was tail biting)