They develop over the course of several days, maybe a week, after about a month the surface
hardens and a layer of
skin comes off, this, too, is painless. After yet another month (approx) it disappears on its own, with no treatment. I am 34 years old, have never had unprotected sex (or blood transfusion, or shared needles, or anything of the sort), and in fact it first appeared even before I was sexually active.