My 3 white cats had feline acne last year but they don't have it any more.I use ceramic now too for bowls,but I also watched them and there were a couple plastic things they were rubbing there chins on so I got rid of those or hid them.
Plus washed their chins with warm water and nonabrasive soap with a face cloth softly rubbing then pat dried and put an antibiotic from the vet called "Oxydex Gel" for about a week.