It's been well documented to have a droopy lid after cataract surgery; best to wait up to one year to make sure it stays stable. Sometimes it can improve with time. You should get an evaluation by an oculoplastic surgeon to see what your options are. Best of luck,
Droopy eyelids after eyelid surgery may be due to ptosis of the levator muscles of the upper eyelids. The ptosis may have been present before and know is unmasked. An evaluation with your eye doctor is important to rule this out.