They can be warts or molluscum if they are spreading.
Warts are tumours or growths of the skin caused by infection with Human Papillomavirus (HPV).They are contagious when in contact with the skin of an infected person. They can be transmitted. For small warts several medications(like podophyllum resin, Podofilox (Condylox), Trichloroacetic and bichloroacetic acids, Imiquimod 5% cream and interferons) are available, which can be applied directly to the surface of the warts.Other treatment options include electrical cautery, surgical removal, Carbon dioxide laser treatment and electrodesiccation.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
I forgot to mention that I masturbate and the craters aren't on my shaft they are on the bottom area near the frenulum could it be scars from the friction cause I never used to use lubrication