If you must eat dairy, then switch to non-homogenized, whole milk from the natural foods store. Even better, see it you can get milk straight from an organic farmer. And don't eat any "hard" cheeses, but eat non-homogenized curd cheeses instead.
I must emphasize NOT homogenized! The homogenization process does something very wierd and indigestible to the milk. Read this forum, use the search function and enter "homogenized or homogenization". Fats were never intended by nature to be cut up like that.
Something else I would like to say seriously, as somebody who had this unfortunate skin condition and cured himself of it: knock off alcohol, and go to more parties. Strange but true, the combination of reduced toxins and increased laughter will do wonders for your skin.