Just keep an eye on it - often. Do not put human medicine on it, just clean it with a warm damp cloth, not too often maybe once a day if it looks crusty. If it is scabbed over and not getting worse, just watch that it heals. I say not to put medicine on it because cats lick their paws and whater medicine you put there he will likely lick it off and ingest it. If it is looking infected (swoolen and oozing) you should call a local vet.
