I noticed after a yintang treatment that my eyelids not only feel "heavy" (tired) but I now have "folds" (where the top part of the eyelid folds down over the eyeball portion) that I never had before. I bled from the treatment after the needle was removed and subsequently the following morning. I also noticed the needle was inserted on the bridge of my nose as opossed to between the eyebrows as in the past treatments received by other practitioners. Could the positioning and deep instertion of the needle caused the "eye folding"?
The point yin tang, which you are describing, will very commonly bleed. It is also a pretty commonly used point that has strong effects on overall relaxation, etc. As far as nerve damage, there really isn't a nerve there that would have an effect on the eyes, so I can assure you that you do not have "nerve damage" in that area. I imagine the point (and others used) could relax facial and neck muscles which I suppose could lead to some sort of an effect that you are describing - but it would inconsequential and quite rare. To comment more particularly, however, I would have to know your whole case (i.e. why you were seeking treatment) and what points and techniques the practitioner used.