Hello, I am a 16 year old boy from the U.S. Ive had a big dark patch of skin in my penis shaft. This patch has been here for 2-3 years already, but I haven't really worried about it until now, I searched online and found a couple articles that said that change in color can be an early sign of penile cancer, but I have looked at the other symptoms as well, and I don't have them. Can someone please help