I have been a poor sleeper for years and it was definitely worse after my PKR.
Even small amounts of discomfort, which don't bother you during the day will keep you awake.
Here are the following tips that I found useful.
I iced before bed and then slept with my knee resting on the open iced water jacket of my Aircast Cryocuff ( refilling with cold water when I woke to go to the toilet).
I got a short prescription of zopiclone from my GP, which I interspersed with diphenhydramine ( Nytol in UK) from the chemist, to avoid any tolerance. Later I gradually switched to herbal valerian and melatonin.
Some people find magnesium helpful, but it didn't do much for me.
Limit any caffeinated drinks after about lunchtime.
In the early stages after surgery, just rest and sleep when you can. But later, try to avoid daytime naps and get back to a regular bedtime, avoiding any blue light/ screens before bed.
Lack of sleep is miserable. Good luck.