Young guys. You liked someone, worked up the courage to say something, and got rejected. Maybe they were even really mean about it. You're not wrong to be hurt or angry.
Here's how to deal with it.
It is okay to be selective in who you let see you hurting. If you repress it around most people? That's not bad, if that's what you need to do to get through. That's why knowing who you CAN trust to be supportive is good
You'll likely get rejected often, for a variety of reasons. Some you can work on. Some you can't. None of it means that you need to buy into bullshit like Pick Up Artists or Incel rhetoric. That shit is idiotic. It reduces people to things.
Well, you may not like this, but if you can, consider crying.
"What?"
Seriously, it fucking helps. I'm not saying "Bawl your eyes out the second it happens" but if you can find a safe place to do it? Do it.
Go write shit down in a journal. Go engage in a contact sport with some friends. Practice a hobby for a while. And yes, if you can do it safely (IE where you won't draw assholes down on you to make you feel worse) go ahead and cry.
Every time a relationship has ended? Yep. Wept. Because it helps. It's a safety valve for stress. Your emotions feel like they're ripping you apart? Vent them. It's that simple.
Don't dwell on it. Yes, it's your pain, and you're allowed to hurt. But don't pick at it. Don't go over it in your head. Don't give that person another thought. Accept it and move on as fast as you can. Don't let them have any more of your time or thoughts