My cat gets "outbreaks" that sound similar to what you describe.  The first
time she had it I took her to the vet.  My vet called it feline acne.  It
happens to her maybe once or twice a year and is temporary.

It's cat acne, and pay no attention to the posts that tell you to avoid
plastic bowls because they "harbor bacteria".  Or if you do, ask for
scientific studies rather than anecdotal evidence, as proof of their claims.

Acne is not fatal.

As others have said it sounds like feline acne. Make sure the cats bowls are
kept very clean. Some recommend switching from plastic bowls to metal or
ceramic. Probably not a bad idea as plastic can be more difficult to get
clean (likes to hang onto the oils from foods).

The problem with the acne is that it can get infected. My recommendation is
to keep the bowls scrupulously clean and clean the cat's chin after meals.
If that doesn't help try 2.5% benzoyl peroxide. This should be available in
drug stores. Read labels as some human acne preparations are 10% benzoyl
peroxide and this probably is too much for the cat. If this doesn't clear it
up or it appears to be getting worse then consult with the veterinarian. The
cat might need an antibiotic.

W

Could be a few things - but probably acne. If its not infected keep the area
clean with just warm water or warm saline.  If it doesn't seem to clear up
have your vet take a look.

As others have said, it sounds like feline acne. The bumps aren't painful now
but they will be if the cat is scratching them or they become infected--and
then it can be an ordeal to eliminate it.

Our cat had a mild case of a couple bumps under her chin. We couldn't really
see them well because her fur is so thick but when we wiped them with a warm
washcloth, one of them started to bleed. We used an antisceptic cream made for
use on pets, and after a couple days the acne disappeared.

The cream was just something we bought at Petsmart as part of a pet emergency
kit, but you could buy it singly. I would try that first but keep an eye on the
bumps because if it gets worse, you should have the vet treat it.

We only use ceramic dishes so that wasn't the cause. I think it might have to
do with her favorite food, Science Diet Oral Care, which even our vet remarked
seems to make her fur feel a bit greasy. This food does help delay dental
cleanings but I think we're going to have to cut back and get her to eat
something else.