dog nipple tumor

Question
Hi, my landlord has a dog which has something that looks like an ulcer on its nipple (it bleeds). It had puppies around a year ago but its nipples are still swollen and she looks pregnant (but can't  be). My landlord claims she is just obese, and that he took her to the vet and the vet said she has a tumor, that the tumor would eventually go away, and that it is good the dog licks the wound. He gives her penicillin to prevent infection. The dog looks tired and sad most of the time. I am worried my landlord is not telling the truth. The dog also has pink patches of skin, she is white, (which I think are fungus) under its neck and on its hind leg. They don't seem to be spreading, but she does lick and scratch them. The landlord said they are related to the tumor. My question is, could a vet really recommend the dog keep licking the ulcer and that it will go away, to just keep an eye for infection and give penicillin. Could her fatness be related to this tumor? What other thing could it be? I want to make sure so I urge the landlord or take it to the vet myself. Thanks!!!

Answer
Mammary tumors don't just go away!!!  Licking a wound can help to keep it clean, but the problem is deep in the mammary tissue.  For a skin infection, a shot of penicillin probably won't do much.  Often there is a communication gap between what the vet tells a pet owner and what the pet owner tells others that the vet said.