Hello! That's a good picture of an area that's potentially difficult to photograph. It seems to show a mass attached to the lining of the mouth, which does look abnormal. Possibilities include cancer (aggressive or benign) and also other kinds of hyperplasia (cell overgrowth) e.g. cushioning against pressure exerted by an opposing or infected tooth, or an epulid (that's a long shot - most epulids wouldn't look like this). Unfortunately it is difficult to tell from looking which of these things is likely in this case and if your vet isn't sure, they may want to take a sample or remove the mass. Particles of food can also get caught in masses in this area. We would definitely advise showing it to them.
https://vethelpdirect.com/vetblog/2019/11/04/my-pet-has-a-lump-what-should-i-do/