[mpeastend]

Been through this many times with my cats....what everbody else said, it's infected & has abscessed. Get that cat to the vet ASAP. He will sedate him, lance, drain & debride/clean out the wound. He will give rabies & feline leukemia shots as well. They now have a long-acting anti-biotic which is ideal for this situation: one shot of Convenia (based on body weight) takes the place of oral anti-biotics 2X a day, and lasts for two weeks. They usually send you home with medicated malaseb pledgets (medicated pads) that you're supposed to wipe the wound with & pick off the scab so that it stays open & oozing. If it closes up, it can abscess again but I've never been successful with my cats in this regard...they won't hold still. If the initial cleaning is thorough & Convenia is given, as long as they're in the house for a couple of days, they'll probably be OK with no re-infection. That looks bad & probably smells bad too. Vet...right away!