How to fix my droopy lower eyelid?

Thank you for the photos. I don’t see “droopiness” here but you do have a negative canthal tilt, where the outside corner of the eye is lower than the upper. A lateral canthopexy brings the angle into the correct position

You would benefit from a mid-facelift. This can pull up the cheek and the skin around the eye to give a more lasting result.

Best Wishes,

Gary Horndeski, M.D.

It looks like you may have had a previous lower eyelid, blepharoplasty with excessive removal of skin and or obicularis muscle.
Regardless of the ideology, a canthopexy or canthoplasty would be the most appropriate procedure.
I suggest consulting with oculoplastic surgeons in your community.
The procedure can also be done by plastic surgeons or facial plastic surgeons. What matters is experience much more than training.
Best,
Mats Hagström MD