What Causes Itchy And Bloody Bumps On Top Of Vagina?

I have been getting bumps on the top part of my vagina, not inside. At first I thought they were bug bites, but they keep forming. They aren't red. But they are itchy and if i slightly scratch them, they bleed.After awhile they seem to go away. One went away and left a small black dot. Another went away and left a round gray area. I haven't been having sex for several years. I'm wondering what could be wrong?