The forgiveness is an ongoing thing.
I haven't hurt as bad as I did then, in decades, almost.
My rage monster is much quieter now, my reactions are much calmer, more considered, more deliberate.
I have learned the lesson I needed to learn, that lashing out at others in my pain, is not okay. That intentional cruelty is nothing I can stomach, nor do I tolerate it anywhere around me. I speak up and stop it wherever I notice it.

If I cannot forgive myself, at least I continue working to atone. It's a worthy goal.