Can i use chloramphenicol eyedrops to treat an upper eyelid infection 6 weeks after undergoing lasik treatment?

I never would. In the USA this antibiotic is rarely used and only when it is the only available drug that kills a specific type of germs. The drug in even tiny amounts has triggered the bone marrow to stop making blood cells permanently in a rare but important side effect. I still recall the kid who had the reaction ~50 years ago & died.

You should always follow up with your surgeon if you are concerned. In general most LASIK surgeons include at least 90 days of follow up in their standard postoperative regimen and up to 1 year in some cases. Dont ask a forum like this; ask your surgeon.