Her eye doesn't seem to be irritated, not red or anything, nor does she seem to be rubbing it. I haven't seen her rub it once.
There is a possibility that she got some Frontline in it on Tuesday when I applied it (although I'm almost positive she didn't), but I would have thought it wouldn't be getting worse almost a week later.
Do I need to call a vet? What might be causing this?
Here is the normal eye (also of the weird fibers in her left eye):

and here is the eye that's losing hair (this picture doesn't look as bad as it is):








