Hello, I have noticed dark spots on the tip of my penis. One is considerable bit about 1/4 of the total of the head. With some other spots that seem that don't a shape. Below on the skin, (not on head) I can see other spots that look like regular moles. I am not really sure how long they have been there because I am not circumcised and until recently I was not able to pull back the skin. What could it be?