I have a 12 year old golden retriever that has developed a red bump on her skin under her fur. The lump is not painful to touch and she does not seem to notice it, but it has grown quite a bit in the last few weeks and I can see little blood vessels inside of it. She has a vet appointment in 10 days, but I am really hoping someone can tell me if they recognize this bump in the photo and tell me what it could be. I have putting castor oil on it which is why it has goop around it. She is also panting a lot, regardless of the room temperature.