As long as he is not losing weight I really see no reason to be worried. BP's will go off feed for various reasons. You can take him to a vet if it will make you feel better. Some snakes will eat while in shed and some will not. I have a baby BP that will not eat while in shed and lately he has been rather hissy. You can try to offer your snake a meal once he is done shedding and see what happens.