ALA as a solution for discoloration
Massappeal is right it is hemosiderin.
My understanding is that during jelqing blood is forced into the interstices where it is consumed by macrophages. Over time the macrophage hemosiderin accumulates because of overloading the removal mechanism.
The way that this is treated dermatologically is with lasers.
However when hemosiderin accumulates in the body it is treated with chelation. Desferal bind to hemosiderin and not hemoglobin.
So, for our purposes I believe a topical chelating agent would be the best bet.
My suggestion is Alpha Lipoic Acid. It is an anti-oxidant, water and fat soluble, small enough to absorb through the skin, has wide spread cosmetic use and is cheap and readily available.
I am currently experimenting with adding it to my minoxidil/contact lense growth accelerator lube solution. The only caution I have about ALA is that it could be unstable in liquid, so you might have to mix it every couple of days.
Or you could try any number of commercially available ALA creams.