Acne can be an annoying skin condition to deal with—though let's face it, for many of us, it's far worse than annoying as it leaves us to deal with scarring and more. We may feel even more frustrated if this skin condition cleared up after puberty, only to later reappear in our 20s, 30s, or 40s. How is that even possible? And what can be done? - What Causes Adult Acne? - Researchers have found adult...