Hi Corrine, I agree it may be an allergic reaction to something, she may have been bitten by something while playing outside, or even irritated it on something like a stick, or on the grass, or it is possible it could be the witch hazel, but probably not since it's just one eye, and her skin and folds are not irritated by it. Have you tried giving her a Benadryl, to see if it is an allergic reaction to something? Does she have any swelling anywhere else like her face? I would keep an eye on her and take her to the vet if it doesn't get better. I hope it clears up soon. These guys are so sensitive to so many things. Please keep us posted.