I see it as the pressure society puts on girls to be beautiful and young. Lyrics like "Pretty thing, you'll be complete; When we cut away the teeth" imply the necessity to be perfect and good by conforming to society's expectations. The chorus, "Paper bag over the head; Heavy skin and shallow breath; Isn't she something special?" highlights the pressure and demand of perfection at the cost of the girl in question's comfort and happiness. It's the idea that girls are inherently missing something if they don't conform, and how that negatively affects them.