http://www.advancesinhealth.com Many things can set this chain of events into motion. Hormonal changes are the culprits for teenagers, causing a cascade of events that interfere with normal skin function from several angles. But even adults can get acne from steroids, testosterone treatments, drinking too much milk or even just stress. Anything that irritates the skin can also cause a breakout and just resting you chin in your hands is enough to get the eruption started in some folks.