i find when i am on pred i get more like a rash than actual acne on my face and neck. oddly enough i found a zinc creme, like a diaper rash creme works the best on it. I put it on at night (cause its white and thick) and wash it off in the morning, a couple times a week or every other day when it gets really bad.
I use to use it if i got a bad pimple and needed it to clear up fast, then the pred rash/acne hit and said what the hey, its still there but not nearly as bad as if i dont use it. Something to try and its much cheaper than pro active