It's probably feline ache and it's treatable. It usually is under the chin but I've heard it can pop up (no pun in intended) in other areas. Anyway, as I said -- it's treatable. Here's what I do since abys are prone to it. I use Stridex (alcohol free) pads with a tight tooth flea comb. I put the Stridex on every other day and comb it the opposite way of the coat. I don't use any plastic dishes as that's the most probable cause. It can also come on with very oily dry food so the dry food I use is not very oily. I only feel on paper plates, glass or ceramic dishes. Use the pads every other day for about 2 weeks and then once a week after that until you see it's under control. Hope this helps.
Snowball has had some trouble with feline acne recently too. I had the problem cleared up once, and then it came back. When I took Snowball to the vet for a checkup, I had the vet check on his acne problem too. The vet gave me a tube of Panolog Cream and told me to apply it to Snowball's blackheads twice a day for 10 days. It worked and the blackheads haven't come back!!!