Hi, I noticed this about 6-8 months ago. It was a small black dot on my penis shaft near the midline. I have noticed that is has increased in size over the last few months and its slightly worrying. It's not painful or anything and it is pretty ovalish. About a few months ago I visited a pysician and was told if I had any concern and I said yes and showed her the small dot and said it was most likely some debris that got stuck under the skin or something but since it has been getting slightly bigger it is starting to worry me. It is probably a millimeter or so big.