My indoor cat has a sudden swelling on his chin that is painful to the touch, because we have had a stray cat causing problems, I am guessing it is an abscess. I do have injectable antibiotics (farm living) and am curious if that is something that should be done. Unfortunately due to recent circumstances I am unable to travel to or afford the vet. He is monumentally important to me and I would like to take care of this ASAP. Can someone help with what to do please ?