I want to know how much I hurt someone
Why did you hurt this person?
No particular reason, just because my mood was bad at that time.
I hope you're looking for information on this person so you can apologize to them!  When you hurt someone, intentionally or not, you need to apologize for it.  I hope they're doing better!
I don't care to apologize.
Well you should. What you did was wrong, and you should make amends.