I believe in not doing it all. I used to cut myself and then I realized I was getting addicted. I think you should realize what causing you pain and let someone know so you can process your emotions. And trust me if your feeling as if no one cares you truly just stated " if my parents found out they'll send me to the doctors" if you know this , they care because they could also jus not care and go about their day. My scars are healed and I'm starting to look for jobs now. Don't mess with anything on your body a harmful way because the consequences are not so charming.
Doesn't matter what you use, they will find out...best examine why you feel the urge to hurt yourself. At this time you might feel scared, alone, numb maybe. I've been there, I've wanted to die, but you don't have to live that way and things do get better. Hold off slitting your wrists and try talking with someone. Doesn't matter who.
WOW if you what to impress cut from your wrist to your elbow using a splinter of glass
There are plenty of alternative ob<x>jects you could use, but none of them would avoid your parents taking you to the doctor.
*face palm* So if they find that you're ******* blood all over the place they're going to be bothered about what you used? Get real.
Chainsaws are effective