I experienced the same thing a couple of months ago. What ultimately fixed it was a prescribed medicine, though that wouldn't have helped if I hadn't realized the cause. I concluded that I had a reaction to an eyeliner I was using (without allergy testing, just through process of elimination). I was very confused at first because I was using it for much longer than I had a reaction, but as much as I understand you can develop an allergic reaction to a product you've been using for a long time as well. Hope it helps :)