I don't think there is a whole lot you can do at this point. These sort of accidents happen. So,
#1 Don't blame yourself.
#2 Just observe the chick carefully. Make sure the others don't peck at it's eye. Make sure it is eating, drinking and pooping normally.
#3 If the others do bother it, I would isolate it until it gets better.
I don't think the eye will ever go back to normal although it may clear up a bit. It may be this way forever. I have a hen that was born with a bad eye. She is blind in one eye but is doing just fine.
So sorry for your accident.
X 2
It happens - for now you just need to monitor the little one and provide appropriate supportive care. Assure proper intake and output and take necessary protective measures should you see the need arise.
X3 watch her closley.
