The acne caused by fluctuating hormone levels is from the stimulation of the sebaceous glands... causing acne... nothing external will remedy the situation. Topical OTC medications are generally ineffective.
I would venture to say that if you have had no problems with acne by the age of 21... assuming you are primarily physically mature... then the introduction of exogeneous androgens should not have much of an impact in this respect.
Accutane would work, however, it takes a bit of time to work... enough to make its use minimal for cycling steriods for small periods of time.
I do not personally see much you can do for preventive measure except reconsider the use of anabolic steroids if physical looks (ie. skin) are of the utmost importance to you.