It has nothing to do with cancer. You are going to be fine. It would be the same if you accidently scratched any other part of your body. Don't worry too much about it.
I accidently scratched a mole on my upper arm and it started bleeding. It didn't bleed heavily and hasn't started bleeding again since. But my upper arm now really aches. Could it be cancer or could it lead to it?
I doubt if they are even related at all.
Heard that some kind of moles can transform into cancer , if the wound hurts so bad then don't wait any further consult a dermatologist , they will conduct some test and prescribe the proper medicines , guessing and worrying you can do it later ,please try to act fast