My boyfriend has a tom cat. He is a year old. He has a fat bottom lip. I took him to the vet a couple of months back. They gave him antibiotics and it appeared to go away. Well it has come back. My boyfriend took him to the vet again they gave him more antibiotics but they didn't do anything. And by the looks of it his lip has gotten worse since last night. The poor little guy is constantly licking his lips. We cannot take him to the vet until Tuesday as it is a holiday (thanksgiving) in Canada. I called the vet and they said unless it is a big emergency that it has to wait until Tuesday.
Has anyone experience this with their cat?

Nadca2, I've never seen it myself, but this is what I found for you:

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Why does my cat have a fat lip?

Answer A swollen lip in a cat may be caused by such things as chin acne, tooth root infections, tumors, insect bites, etc. For an accurate diagnosis, it's best to visit your veterinarian for a good look at your cat's lip. After a complete exam, treatment can be started to target the underlying cause.

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It's from healthypet.com