I have a big mole on my back and I hit myself and it started bleeding and part of it came off? Should I go to the doctor? I put antiseptic spray

Bleeding mole. Once the area has healed in a few day or so, it is wise to see a dermatologist for evaluation. It may be simply a non cancerous mole that was " caught" and will heal completely. Other times, a dermatologist may determine the are should be removed and tested because it looks suspicious for skin cancer.