Yes I agree that it looks like feline acne to me too. What kind of bowls do you use to feed your cats? If you're using plastic ones then thats most likely the cause. You should use stainless steel or ceramic bowls because you can clean them much better than the plastic ones.

My cats Sunny,Pearl,Sky,and now Ziggy have small breakouts from time to time and I use a warm washcloth to help remove the blackheads and then I put some hydrogen peroxide on it. You can do this 2 times a day and hopefully it'll go away in a few days to a week. Sunny also tends to break out when he becomes stressed out.

I now use stainless steel dishes for water and food but Pearl and Sky like to eat off of plastic place mats. I've also heard that cats with white chins are more likely to get this. It's probably just more noticeable on them. Good luck.