What Can I Do About my Skin Fold on One Eye? (photo)

The extra skin fold in your left upper eyelid (picture taken in mirror) is due to either genetic or traumatic injury to the muscle that elevates the upper eyelid (levator palpebrae superioris, LPS).  This situation is referred to as ptosis (droop) of your upper eyelid.  It can be corrected by shortening the tendon of the LPS.  This will eliminate the double fold in your left upper eyelid. 

I recommend you seek an evaluation by a Board Certified plastic surgeon or oculoplastic surgeon experienced in eyelid ptosis surgery.  

You have a condition called ptosis there are variety of reasons for this. It comes down to difference in the mechanism that opens your eyes- and it can be corrected with surgery but usually need surgery on both eyes because of complex reflex- your brain detects less light going into your right eye, your brain tells your you to open your eyes wider- but your right can't because you have ptosis therefore you open your left eye wider which makes the asymmetry worse. 
See a specialist plastic surgeon or ophthalmologist in your area to have a correct diagnosis and if deemed appropriate, surgery to correct it if is becoming a problem for you,
Wish you the best in your journey,
Dr Leo Kim, Specialist Plastic Surgeon in Sydney

Your pictures suggest the presence of a unilateral eyelid ptosis. This condition occurs when the muscles that elevate the eyelid become weakened or detached. When this situation arises, surgical correction is usually always necessary. The specific procedure utilized is dependent upon the anatomic deformity.For this reason, it's important to consult a board certified plastic surgeon with experience in this area. This surgeon should be able to formulate a treatment plan that addresses your anatomic findings and achieves your aesthetic goals.