I was hanging out on my patio last night with my 1 year old english bulldog. Out of nowhere, I noticed that she had a large lump on her neck, just beneath her jaw in the center, it had not been there 20 minutes earlier (we rub her neck nightly). It's about half the size of a tennis ball, but it'll get bigger, then smaller, and it also moves around. She doesn't seem bothered by it, shes playing and eating like normal. During the night the lump went away completely, but came back after she was awake. I called the vet, they said give it a few days to see if it goes away on its own, but I'm still very worried. Has anyone had this happen to their dog and know what it is?