I am 15 years old and I am generally a healthy person, I have had no medical problems in my past but I recently am worried about my private areas knowing I have Phimosis (it is not a severe case and I am making progress by stretching exorcizes). I have had this brown/blackish discolouration on the tip of my foreskin, it is like an oval shape but is not too large (probably about half an inch). There is no pain, no discomfort, no trouble urinating and the discolouration also has no raise to it, its almost as if it was a birth mark. It is not too dark but is close enough to be called dark brown. There is no bleeding or any fluids coming out of it. I have no idea what it is, I have been reading many forums on it but I am not sure what everybody else is explaining is what I have.
I have never been involved with sexual activity, except kissing so I'm sure it is not an STD. I have had this for as long as I can remember but I also know that it was not there when I was born. I am very worried and want some help on my situation, it would be greatly appreciated.
Thank you.