it can be several things. it the swolen ear painful to the touch? dose the dog have his ears croped? does it feel fluid filled? I dont know much but i was a vet-tech for four years so i can at least point you in the right direction.
Well, if your are able to i would say get him to a vet. I have a tree walker coonhound, and she has chronic ear problems. Once her ear was swollen, and it was a blood vessel that burst in the ear from her scratching at it, because of a chronic yeast infection. We took her to the vet and he drained the fluid, and all was well.
My dog had the same thing. Take him to the vet and they will drain the ear. What has happened is he broke a blood vessel (happens alot) and the two layers of the ear seperated. so now the ear is just filling up with either blood or puss or even another kind of clearing fluid. You could alwayse drain it your self. just take a needle and suck the liquid out
