I m 50+ and noticed, when I went to the toilet first thing in the morning, a bruise about 1.25cm in diameter over the back of the shaft of my penis, around mid-point, maybe slightly towards the base. No discomfort to start with. At night, I noticed a small paler area, may be slightly reddish, in the middle of the bruise. On feeling it, it appeared to be a tiny lump, about 2-3mm in size, completely within the very tin skin of the shaft - I can actually pick it up and roll it between my fingers. Since its appearance, it has got a very slight burning sensation. I have only one partner and have no urinary or other symptoms. Normal erection and no pain during sexual intercourse. I would be grateful for your opinion as to what might it be.