Discolored line of skin on penile shaft.

There is dark grey colored skin going from my testicles to my glans, when irritated by things such as rubbing it turns red, also noticed a dead vein near it. Also the closest affected part to the glans it seems to sort of be making a ring. The line of skin is only on my left side of my penis, and gets wider closer to the testicles. It also has a different, smoother, and slightly stickier texture to it. Towards the testicle side of the penile shaft there is a small crease. The closest thing I could find online to this issue is friction burn? Unless an STD can be carried from birth and only show up after so many years. I have never had sex so I'm assuming it was caused by masterbation. Any information on what it is and how to heal it would be greatly appreciated!