Hormones called androgens overstimulate the skin's oil glands, which frequently leads to a breakout around menstruation. (If you break out along your jawline, this is the likely culprit.) Some women find relief by going on oral contraceptives — aka the Pill — but you'll need to discuss the benefits and risks with your doctor. You might also want to explore conditions such as polycystic ovarian syndrome, which can contribute to acne.