How can my eyelid droop be fixed?

Eyelids can be fixed, but it
does depend on the specific type of problem that you have, neurogenic or
acquired. One can do an operative procedure to actually elevate the eyebrow if
you have good leeway. This will require the expertise of someone with experience
in Ocular Plastic Surgery.

You likely have Horner's syndrome with eyelid ptosis. The only good solution is eyelid ptosis surgery but not sure if enough time before your wedding to recover from as the bruising last about 2 weeks. See an oculoplastic specialist.

I agree that you may have a Horner's Syndrome. I would seek and evaluation and consider other adjunctive procedures to improve the droop.  Sending a picture is worth a thousand words.

Hello,I suspect you have Horner's syndrome.  This is a loss of stimulation to the eye from the sympathetic nervous system.  The thyroid surgery may have injured the nerves that control the sympathetic nervous system to that side of your face.  In addition to the lower eyelid, you may have a smaller pupil and loss of sweating on that side.  There is no cure for this condition, though it may go away spontaneously if the nerve injury was minor.  In the mean time, you may benefit from using an eye drop called iodipine.  This will temporarily stimulate the muscle in your eyelid that the sympathetic nerves are supposed to stimulate.  This will probably be your best treatment for the short term and may work just great for your wedding.  In the long term, if the condition persists, you may consider having ptosis surgery to lift the eyelid.