Should I contact high school clmates 20 years later if I was an ****** then?

If you feel that you need to, I would say yes. If they can't accept an apology then they have a problem. I was picked on all through school,. I'm no longer mad about it, though I wouldn't mind an apology. Time changes things and we all grow up. They'll probably shrug it off, but deep down I think they'll appreciate the effort.