The person that I bullied in school confronted me in front of my friends

The best way in overcoming one's own mistakes is to own it.

Hash it out with the guy, mend things. It might just be an embarrassing past for you, but it sounds much more to him.

Being bullied, it sticks with you. You have to be really strong to deal with it, vocally and emotionally.

When things settle with him, then explain things to your friends. Not many can deny someone who is trying to work on themselves.

Just a suggestion. Best of luck.