I have a quarter sized mole on my back that doc said is fine. today i scraped it really bad carrying a metal rack. it bled a lot. do i need to go to the doctor or just keep it clean?

These tend to have a brisk vascular supply and can bleed more than anticipated when traumatized. Having said that, basic wound care with keeping the wound clean and applying a clean / sterile dressnig should be all that is required. Of course if the bleeding persists or there are other changes in the lesion, circle back with your doc to take another look.