Not sure if it's the same, but our 13 year old cat got feline acne, caused by bacterial infection because we used a plastic water bowl.

We switched to metal, and when we went to the vet he gave us an antibiotic and recommended we clean his chin with warm soapy water on a soft cloth and just gently scrub his chin in a circular pattern. We could also use acne pads (technically has a chemical bad for cats, our vet told us to by gentle strength version) and use those once a day.

Eventually his inflammation went down, and after a month or two he was fine.

I don't know if it's the same as your dog, but I would make sure you have a metal water bowl and gently clean it's chin with warm water. If you can, bring to vet just to be sure?

New to this sub. Sorry if this isn't great advice.