Acne Before My Period

I notice that I would have acne breakout every time my period is about to start. I am not sure whether it is caused by hormonal changes or just stress. But whatever it is, I need to undergo acne treatment. I cannot stand looking at my face in the mirror whenever I have acne breakouts. I can't also stop touching my face, which I am not supposed to be doing. It's a good thing that I am friends with one of the known dermatologist in out town.