This could be a laceration, puncture wound, abrasion, degloving injury, infected cyst or tumor. At this point it is not as important what caused this open wound---your cat needs veterinary medical attention. This wound may need to have dead tissue debrided, likely needs stitches, needs to have a deep clean performed, and definitely needs antibiotics. Also do not allow your cat to lick or chew this wound. Cats have a large amount of bacteria in their mouth that are being transferred to the wound. Also chewing continues to damage tissues, cause inflammation, keep the wound open, and prevent healing. Your cat may need a bandage to protect the wound or an Elizabethan collar to stop the chewing.
Take this cat to your veterinarian as soon as possible.
Take this cat to your veterinarian as soon as possible.
