I am an 18 year old male, and I recently noticed that there is a small knot in my chest under my left nipple. I had noticed that my nipples were dry, but i life weights a lot so I figured they were just raw rubbed by my t-shirt. The dryness has ceased but there is still a little knot. It appeared very quickly, so I am not sure if this is something I should be worried about, or if will clear up on its on as fast as it arrived. Thanks for your help!