Kids do stuff like that sometimes. Now of course, I don't know what you did, but if you've even become friends it can't have been as evil as you feel it was. Anyway, I know how this doubt might feel. I don't have the same experience as you but I struggled for a few years to tell my therapist something I used to do as a child / teen for the exact same reason as you. But then one day I told him, and he actually answered with "so what?"and compared to something he used to do as a kid. Now I can also see how what I did, while not the best thing I could have don, it isn't a tragedy.

When I read your post, I really didn't and don't think you are evil. I think you seem to have remorse for what you did, which isn't the feeling of an ëvil"person (I don't even think there is any purely evil person out there at all). I can sense your pain for feeling about yourself this way. As you can see, you've received support here, not judgment. It should be the same and better with your therapist. Knowing more details about your history, your therapist may understand even better what happened and what triggered you that day.

I hope you find a way to forgive yourself.