Have you ever seen your cat get a swollen lower lip and wonder why? This is super common in cats and happens because of an allergy. The allergy is most often to fleas, when cats groom fleas and flea dirt from their coats it can result in an allergic reaction in their mouths and lips. They can get swollen lesions on the roof of their mouths and swollen lips, usually the lower lip. Much less commonly, this can also happen if they have an allergy to their food or water bowls - cats can be allergic to plastic or metal bowls.
If you see this the first thing to do is to make sure your kitty does not have fleas. If you do find fleas, treating your cat and your home for fleas should help resolve the swollen lip. If you are having trouble getting rid of fleas, you can check out my super helpful video here!
Once you are certain that you do not have fleas, try swapping out any plastic or metal bowls for ceramic bowls.
If the swelling does not improve, or if at any point you are worried about your cat, please consult your vet.