Pls am having some painless kind of pimple at my penal shaft. i have recently been treated for sti and haven't had sex since then. what's wrong?thanks

Spot on penis: I think you should go back and have a doctor check this out. STIs can run in packs, and if you were exposed to one, you could have been exposed to another. Genital warts can be painless, and they are very common. An ingrown hair would usually be painful. Herpes is usually very painful too, so it's probably not that. Syphilis can be painless, but usually looks more like a shallow ulcer. Good luck!