well, i am pretty sure the skin shader can be improved upon, but i don’t have concrete suggestion here.
however, i am missing the brow (shouldn’t it be visible as well, even partly?), and the eyelashes are strange. we should be seeing some kind of small “bulge” where the hair (individual eyelash) enters the skin (and the follicle is), and there has to be some variation in the color of the hair, as well as more glossy.
is this a woman’s eye? if so, shouldn’t we expect more make up?
the tear: it is more likely for tears to come from the tear ducts whose aperture is located at the corner of the eye (google it up to make sure), and certainly not in the middle of the eye. for a tear to come to the middle of the eye, i would expect the person to be looking straight and a little down, and not up.
have you looked closely at your own eyes? do they look similar to your image?
now, there is also a question of the narrative of the image. because the eye reflects so much, you can use it to tell a complete story. are there other people near the person. why is he/she crying? if you don’t have a story to attach to the eye, think of a story, and you will probably come up with all kinds of things to add/change.
i really think you did a god job so far, and there is a lot to be proud of in the picture. but to win a competition, you need to push yourself even further.