My cat's tail has swelling near it's base, about the size of a golf ball. There appears to be a puncture wound on the top, and when squeezed, tons of pus comes out. The underside appears to be scraped as well, there's a pretty good sized chunk of skin missing. That area looks a little inflammed as well. Not sure how he managed to injure it. Could this be a spider bite or the result of a broken tail? Any advice would be appreciated.