I am a 16 year old male and there s this Lump, or welt on left side of penis on shaft. Well I was masturbating and I put my palm on my penis to twist the skin a little bit then I gripped myself quite hard. I was masturbating and I felt a sharp ish pain on my left side. Idk how to describe it, like a vein being compressed? Or something? I can t remember exactly what it felt like. And the next morning when I was washing myself I noticed the lump, or welt, on the side of my penis. The skin there is tight and a little purple, but I believe the purple to be a bruise (I ve had this before from masturbating too rough but never the lump that s there now.) I hope this isn t serious, and I don t want to have to go to the doctor cause it s quite embarrassing.