Re: Red Bump on lower lip/chin
In addition to cleaning the cat's chin area, you should also wash his food/water bowls. If he has plastic bowls, I would suggest throwing them out and replacing them with stainless steel or ceramic and washing them more often to remove oils from food or the cat's fur. Plastic can get tiny scratches in the plastic, that bacteria can hide/grow in. As food and/or oils get left behind, they feed the bacteria and allow it to grow and also rub off onto the cat's chin. The chin is a difficult place to clean; the tongue doesn't reach and their paw is sort of ineffective for cleaning under their chin.
It is a fairly easy "fix". If it doesn't improve over a few days, then I would bring the kitty to the vet in case the problem is more severe.