Hello,
Some of the sagging and drooping eyelids causes are the natural aging process, intake of foods rich in sugar, stress and depression, fatigue, inadequate sleep, smoking, accumulation of toxins in the body, thyroid dysfunction and fluid retention.
Botox injections and a surgical procedure in which excess skin, fats and muscles around the eye area are removed and repositioned are routinely performed.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
I would put 100% clear aloe vera on your chemical burn.