Good news: your late-night slice of pizza probably isn't going to cause acne — that is, unless you rub it all over your face, says Dr. Lee.
The truth is that having acne doesn't mean your skin is dirty, on the inside or out. While there's a tendency to think that acne is the result of not washing your face or sheets enough or eating too much oily food, Dr. Lee says acne isn't your fault. "The truth really is that it has to do with hormones and genetics," she said.
When your hormones are raging — as they usually are in your teenager years — your skin produces more oil. So, naturally, you're going to break out, says Dr. Lee. The same holds true for adult women, who tend to break out during ovulation or in the days leading up to their menstrual cycle. Likewise, pregnancy can affect your skin. "Either it can make your acne worse or it can make it better, just depending on the hormone level," Dr. Lee said.