You have to tell the adult as soon as possible. Don't let anyone experiment on something without adult's supervision.
Well...it has to be about your self so....
Answer:
Have you considered duck tape? If you leave it on long enough it creates the same effect, just you know without blood. You don't have to answer this, but are you using cutting as a kind of outlet? Or for different reasons such as self hate? If you also don't mind me asking, do you cut daily?