Alfie had one of these 2 years ago. It's called a histiocytoma. Alfie started scratching furiously at his ear and when I investigated it the red lump was almost glowing! The vet said it usually goes away on its own accord but occasionally it requires surgery to remove it. Alfie's didn't go away and he had a wee op to remove it as it was in an awkward place at the entrance to his ear canal. The op was a success and he made a complete recovery.