You sound like me. I also developed acne cosmetica -- the tiny patches of closed comedones you're talking about -- due to an awful foundation by Tom Ford. It was way too creamy, emollient and irritating for my skin and my face went nuts. I got closed comedones on my cheeks and forehead for the first time in my life.The moral of the story is: just because a foundation is expensive or has a big brand name like MAC doesn't mean it's worth the price or good for you. (I paid 80 dollars for a near ruined face!)

I remember using MAC year ago when I didn't have skin issues and it gave me a break out near my chin and the lower half of my face, tiny red pimples that disappeared quickly after I stopped using it. I've also known several people who developed bumps and whiteheads from MAC. It is a pretty well known 'trigger' makeup, even for people who aren't acne-prone.

Avene is awesome. Keep using it. Try some of their other products, like their acne oil-free face wash and cream cream for the morning -- personally I found the cream cleanser to be way gentler and more effective than Cetaphil ever was for me. (It's best not to use an acne cleanser twice a day as it can dry you out and compromise your acid mantle, just making you more prone to acne.)

Have you ever tried to treat the comedones with AHA, acid peels or retinoids?I'm starting Differin soon...but possibly every 2-3 days at first to avoid being too dry. Right now I have about 8 closed comedones on my forehead and a dozen on each cheek. I know I don't have it as badly as some people do, but I'm still upset by it.

I have never tried MAC personally, but from my experience on the internet that brand in general seems to cause a lot of people issues.