Yes. Go to the vet they are prone to many things. Could there be a bite there? While you wait for your appointment you could try warm compresses to see if it starts to dissolve. Clean the area thoroughly with rubbing alcohol or betadine each time after. It can be a small puncture or scratch and dirt and dust and bacteria gets in there and forms an abscess. This isn't a substitute for the vet, but if that's what happened it could make treatment go faster. And it may help the vet if you can tell them you were doing that and it was getting softer and the swelling was reducing.
