Hey dude, first I understand your anger and pain of being bullied. Its unfair and horrible to go through, especially when there is no help.
But hear me out. The fact this guy apologised is good. Dont take it as an ego thing. If it was ego, trust me, he wouldnt apologise. He would just ignore you and act like you dont exist. Hes most likely matured, and feels embarassed at how he treated you. It takes a lot for someone to apologise.
Perhaps your anger now also comes from the fact that you didnt / werent able to let him know how it made you feel all those years. Dont be afraid to communicate, the same way he reached out. Just keep it positive.
I was bullied a lot in school, and in my adult life I deal with racists literally every day, my own neighbors are racist. Ive had random people spit on me, call me racial slurs, throw acid in my face, police kidnap me beat me up and throw me in jail for no reason and made up fake charges, a vet killed my dog because of racism, ive had racist doctors i paid a lot of money to tell me im going to go blind in 1 year and theres nothing i can do about it (its been 4 years since then i still have my sight), it was all very angering plus all the memories of getting bullied in school myself to the point where i would skip school from the fear, i was ashamed to let people know i was getting bullied so my family thought i was a nuisance. It got to a point where I wasnt taking shit from anyone on the streets, getting into fights etc. and all it does is land you in a police station, and if you win or lose a fight theyre both losing scenarios... you knock the guy out and you just end up watching your back and looking over your shoulder for the next few months because theyll want revenge. Ive been in fights and looked out for months and then think everything was cool, only to see the guy looking for me with his boys a few weeks later. Its a never ending cycle when you let those situations happen.
Ive written suicide notes when i was getting bullied and it got ignored. I attempted suicide in college and it wqs a failed attempt, but that night I randomly got an email from a family friend asking if i was ok because they noticed i was always sad. This was after I prayed to God that i want someone to understand how I feel.
However, that wasnt when i got wise. It was when i just let the anger consume me. I didnt have anything in my mind to correct it. I was a nice guy, but if I felt someone wronged me or was trying to bully me, id turn into a demon. Well, one day I took it too far, i didnt hurt anyone I just got myself in a dumb situation out of anger and was facing up to 6 years in prison. Man oh man did that fix me up. I never felt such a feeling in my life. All that anger just turned into deep deep regret. I at that point felt I had to end my life, and it was at a time i didnt want to. My life flashed before my eyes and it made me realise 2 things.
I forgave all the people that did me wrong in my life. I didnt need to love them, but I forgave them. It lifted a huge weight off my shoulders.
The only moments and memories my mind cared about in the moments leading up to when I believed my life would end were the positive ones. Even with all the unfair things that happened to me, and the bad ways people treated me, they seemed so irrelevent in those moments, my mind was racing to find all the good memories and the good things I would leave behind. I just got an overwhelming sense of how important and better it is to live a life made of good memories, and that we can rise and learn from our bad experiences. Basically when my life flashed before my eyes, the only things of value were my good positive memories. It made me feel "Why did i spend my time letting others dictate how i feel and how i live my life".
Its easier said than done, but you need to just not even pay any attention to negativity. Whats happened in the past is shitty, but you have that on your side as a piece of armor. You already know what it feels like to be dragged through the mud, something a lot of people dont have. Let it make you a better person, not a bitter person.
Also, that situation brought me closer to God. You might not believe in God, but I never prayed to God so hard in my life after facing serious time. I was provoked by a bully who was a figure of authority. I asked God to give me a sign that he heard my prayer. My room lights were off, but when i opened my eyes after my prayer I looked up and only the light above me was on, even though the switch was off. So i took it as a sign, my prayer got answered. From then on I lived my life differently, more positively. I do slip up from time to time but i feel im much more wiser.
Hope this helps