Actually, many women crave chocolate right before their menstruation cycle. This is because women usually have a deficient amount of Magnesium in their bodies during that time, and chocolate has high levels of Magnesium. It's happened to me; I almost went crazy wanting chocolate, didn't get it, and woke up from a really bad leg cramp in the middle of the night after that because I was low on Magnesium (it hurt really bad, too). When your body lacks something, it craves the most efficient/tasty source to the ingredient you're lacking.
Our bodies truly are amazing.
Chocolate doesn't give you acne, by the way. Oil glands release oil onto your face to keep your skin moisturized. The amount increases with hormones, and some of the oil becomes blocked in pores, causing blemishes. Chocolate and sweets have nothing to do with how much oil your glands produce.