You messed up. So what? Everyone messes up. Everyone.
Anyone who tells you that they have always done the right thing is a liar.
But as an enlightened person your job is to keep moving forward. Forgive yourself and resolve to do better next time.
Odds are, the person you mistreated will cross your path again, and you will have a chance to make things right. Or if not, you will find another way, to pay it forward with someone else.
And remember the person that you feel you disappointed the most – yourself – will always be there for you to make things right. That's the first job of forgiveness, and the first step towards enlightenment.