what the fuck did I just read
"because how the hell are you supposed to tell someone you just wanted to see how it felt? how the hell are you supposed to tell someone you just wanted to watch yourself bleed to death?"
By saying what you just wrote, but with your mouth. How did you expect them to help you when you lied? Don't be stupid.
You're not crazy. Crazy is shoving bugs up your ass because you think that doing so will prevent an airplane disaster on Tuesday, November 14th at 5pm est. Crazy is talking to the plywood box you live in because you think it can give good stock advice. Crazy is losing all touch with reality because you literally have no ability or inclination to tell the difference between the real world and the shit your brain makes up because it's all real to you, and you are willing to argue reason, fact and evidence against it. There is no doubt in crazy. If you can question your sanity, you still have it.
That's not to say you're a picture of mental health. You're not. You've got a thought/impulse disorder at least, with a little bit of your brain trying to convince you it's ok to be an asshole if there's an acronym for it. Hate to break it to your brain but it's not.
If you were a sociopath, acting out on it in ways that harm yourself or others would just mean you are an incredibly STUPID sociopath. It doesn't mean it's ok to be an asshole, or to do shit you know is wrong/stupid, being a sociopath means you don't care about the personal world of others it doesn't mean you're unaware of it, or think the rules don't apply to you (most think they shouldn't, and treat any that can be gotten around with blatant disregard, but that is a different matter.)
Don't worry, though. You are not a sociopath, you are a regular person with anti-social thoughts, and at your age, it's hardly surprising. See a shrink, and don't fucking lie (you're not the first idiot who cut himself to see what it looked like, and you won't be the last) or you'll be wasting his time and yours as well as your (or your parents') money.
In my unprofessional opinion:
You just need to smoke (more) weed, masturbate more often, get a job or a goal or something else to focus on and you'll be fine, probably. If you start having "intrusive thoughts" then actively focus on something else. Don't try to 'not think about it' because the brain doesn't work like that and you'll think about it more. Just focus on something more interesting, like a book or game, that will actively engage your mind.
Everyone has fucked up thoughts sometimes, some of us have them more often. Mine tend to be of animal abuse, kittens being smashed in a closing sliding glass door and the like, though I love animals and wouldn't ever do that shit to one. Plenty of people have had the same thoughts you're having. The problem arises when you give them too much time and attention instead of getting on with your life. Focus on that shit like it actually matters and you're probably going to end up doing something incredibly stupid and end up in prison for the rest of your life getting buttfucked hourly by the ugliest guy you ever saw.
There's a healthy (read: not fucking up your own life) way of dealing with everything. Find it.