Need to ask about lower eyelid retraction surgery, it's cost, benefits, and risks. How safe it is to have this surgery?

Lower eyelid retraction is safe, based on surgeon's experience. See following link for more details. The repair may require spacer graft inside the eyelid.

The first question is whether you are having any further eye  muscle surgeries, because that can affect the position of the eyelid. Assuming you are not, then the next step would be retraction surgery. The surgery is covered by insurance but there may be an out-of-pocket fee depending on your specific plan, so I would suggest discussing it with your surgeon and/or practice at which you will be having the procedure. It is a safe procedure and there are different approaches depending on the examination. I would suggest seeing an oculoplastic surgeon to do an evaluation.