I hate to share this gem of info, but I get acne when I am pregnant and it doesn't go away until I am done nursing. It is big cycstic under the skin acne. After trying numerous solutions and talking to a dermatoligist and a make up expert, I have determine there is absolutely nothing you can do to prevent this type of hormonal acne. The most you can do is treat it when it appears. Proactive stuff is the best but very chemically. Tea Tree Oil works for some people (not me).