Nobody likes dealing with acne, especially when you're an adult. (Weren't our prime years of breaking out supposed to end in high school?) But the truth is, acne can occur at any age for a whole slew of reasons, even if you never broke out as a teenager. Luckily, this common complexion issue can be treated over time. Celebrity dermatologist Dr. Susan Evans explains the hows and whys of adult acne - along with over-the-counter and prescription solutions for this problem.