Hi, Welcome to JustAnswer. I am a licensed veterinarian and I'm here to help you. Sorry that it has taken us awhile to get back to you. Fergus doesn't feel very well at all so he's not grooming himself normally. . .hence the oily/greasy fur. This may or may not be related to the lumps. Have the lumps been by his tail for very long? Is Fergus eating and drinking well?