Swollen Jaw ,pitbullMix, need help!

My Dog Oliver, was acting very strange one day. He was weak, and looked feverish. He is usually very active and quite the guard dog, cheerful and playful. He is an outside dog, but I brought him in my room to take care of him. I tried to give him nice cold water and even beef jerky as a treat and he couldn't eat it or chew. I saw that the right side of his head was abnormally swollen, mainly around the jaw. We took him to the emergency vet, and they kept him a few days and took blood samples and were able to open his jaw to see if he had a tooth abscess and they took xrays also. He was given antibiotics and steroids. They said they couldn't find any cause or problem, and was very frustrating for us because not only was that visit and procedures over $1,000 the swelling is now returning. The swelling did go down while he was on steroids. He is eating and running about normally. On the side of his jaw where the swelling is there is a lump on top under the skin that is soft, but the actual jaw muscle both lower and upper towards the top of his head is much larger that the other side. The emergency vet suggested an MRI if it continues, and I'm really scared he has cancer or a tumor. I have been doing some research online and the closest thing I found was craniomandibular osteopathy, but it says that that is mainly in new born dogs. Im really worried and not sure what to do next.

[Dan Sims, DVM]

If the swelling is on the top jaw under the eye a carnassial root abscess is likely
and a dental xray and extraction will solve the issue
Dr Sims

[Ashmanz]

here is a link, I added some pictures of Oliver so you can see how swollen his right jaw is

[Ashmanz]

http://www.ash-steenkamp.com/oliver.html