12 year old Pomeranian eye swelling (PHOTOS)

My dog, Bear, suddenly grew this swelling around March 5th. It was a small bump the first day (Monday), then grew later that night (photo #1) Throughout the week, it would grow and shrink - last night it grew to the biggest it has been (photo #2). We changed his food last week to Nutro Natural Choice, he lives with another older dog and cat - in which, they all get along. The swelling is like a bruise - doesn't hurt with a light touch, but does with pressure. We think it's an abscess tooth or a bite from a bug. We're gonna have to eventually take him to the vet if it doesn't get better - we just don't know much, it came out of nowhere. 

Hello!  If the eye itself is injured / moves forward / swells etc then it is always an emergency, although in this case I think you are talking about an area of face that is close to the eye.  This might well be an abscess, an area of infection, perhaps as a result of a bite wound or tooth root abscess from underneath.  If it is such an infection, then it is unlikely to get better on its own but rather get bigger and possible burst out, but be painful in the meantime.  Such infections can also get into the circulation, making the patient feel lousy.   For this reason, we would recommend seeing the vet as soon as you can.

If you are in the UK, they should have someone available on the phone now to triage the situation.