Could be the start of blepharitis. Stop wearing mascara for a while (and buy a different brand). Never go to bed without washing your face, and otherwise be scrupulous with your eye hygiene, washing your eyes with a hot, clean facecloth at least twice a day. It may just go away. If it doesn't, you'll have to wash those eyes at least four times a day. If you are under unusual stress, chill out!
Too little details. I would suggest you see an ophthalmologist.