Well, generally speaking, when dilated pupils occur, the black part of the eye will be bigger than normal one. And that can be annoying and painful to many people. Also, you should know that some factors, such as high blood pressure and anxiety, drug use, illness, and trauma can lead to it. To treat it, you should make sure you wash your eyes frequently and apply cleansing eye drops to get rid of any foreign particles. Also, you can try some cool teabags and cucumbers under your eyes. And that can be good for your situation.