I had to wear sunglasses for like 5 days because my eyes were so sensitive to the light. From what I recall, no damage occurs if you don't wear the sunglasses, your eyes are just EXTREMELY sensitive so I don't think you will not want to wear the sunglasses. I only had a little bit of pain like an hour after the surgery. I took a tylenol3 and I didn't have any pain after that. I did have to take a lot of eye drops though. Since your eyes are covered for a couple days, no oxygen gets to them, thus your eyes are very dry and itchy. and I think there are some eye drops so your eyes dont get infected or something.
from what I understand it is supposed to fix your night vision, but sometimes it doesn't fix it for some reason. for example, I sometimes have a little bit of an issue at night if its raining, but its really not that big of a deal. getting the PRK was one of the best decisions I have ever made. I highly recommend it.
Edit- not sure if its been said yet, but when you get the PRK, your eye sight starts out worse and then gets better over a course of 3 months or so whereas the LASIK is like 20/20 or better right away.