Medicine and questions?

Is there a medicin to where if i was to take it then cyt myself it wouldnt hurt kinda like a medicin that made your skin not hurtable but if something went through like if being shot or something that hurt just like cutting with a razor how can someone make that not hurt cause this kid at school pulled a razor out in the broom and cut a deep cut all the way down his arm then his chest and it didnt hurt but when someone stabbed him with a pencil it went like far through his skin and hurt btw he stabbed him cause he said he caint feel pain is there medicin that can cause that or was it drugs