I once had a bully. When I informed my father about it, he asked me, "Did it hurt more than when I beat you?"

Me: “No”

Dad: “ Then strike him when you meet him the next day. If you don’t hit him, ill hit you. I'll stand by you if you encounter problems with the school. Even transfer you to a new school if necessary. But you are the only one who can save yourself.

Me:” I'll lose, and he'll still bully me”

Dad: "Then, without giving him any prior notice, punch him in the face again the following day. Till he quits, continue doing this. Whether he harms you or you lose has no bearing. Just be sure one of your blows hurts. He will eventually get sick of you hitting him without notice”

So i did just that and to my surprise I won the fight and he didn’t bother me again. Had other bully later in life, and they were more mental than physical which for me it was worst. But all of than ended in the Uni.