A childhood belief about general

my mother would say to me when i was little, and either crying up a storm or making a face at my little brother, 'your face is going to stay like that; you're going to get hydra-false-face.' i always that that was a real disease, not something my inventive mother made up; and to support her, when i once got wise enough to question her, my older sister showed me a pamphlet with the comedy-tragedy masks on the front and said 'this is what you'll look like'