What Causes Increase In Nipples Size In Males?

Hi. I've been weight training for about a year now, im 21 years old.. I take supplements like Glutamine, Creatine, HMB Tabs, BCAA's, Multi Vits. No steroids. And for the past two weeks ive noticed an increase in my nipple size.. Much more in my left nipple though. A big increase in size, puffyness and the nipple always seems hard and white. Really worried about it, could do with some advice on what maybe causing this and what there is too do? Thanks a lot. Adam