I have had 4 ptosis surgeries and still have poor results. Will a 5th surgery worsen my eyelid?

You really need to seek out the best oculoplastic surgeon for this you can.  I recommend Alice Goh SIew Ching at the International Specialist Eye Centre Malaysia, Kuala Lumpur.

Congenital or childhood ptosis is a difficult problem, but it is correctable. Because the cause is related to underdevelopment of the muscle that opens the eye, the surgical approach differs from the one for older patients in whom the muscle loses tone and becomes lax over time. There are two general approaches, and it depends on how the surgery was done for you. If your doctor made an incision through the skin to tighten the muscle that opens the eyelids, then generally speaking, the more you do the surgery, the more likely it is there will be scarring of the muscle and the more challenging it will be to raise the eyelid that way. The other type of surgery involves suspending your eyelid from your eyebrow so that you can raise your eyelid by raising your eyebrow. That surgery can be effectively done and repeated and does not generally become less suscessful over time.