I notice a pinkish color on my ball python around the lips where the tounge comes out and has darkend. He now has two dark lines goin down his lips, ending at the "chin". I don't see anything else on him. He eats well (sometimes skips) at least every 14 days. Has no discharge or anything like that . is this mouthrot or just dirt. is it normal to have pinkish color where tounge exits. His substrate is newspaper.