When Haruka asks one of the shopkeepers about getting a hand mirror, they say that she would never be able to afford it because they're incredibly expensive. This seems odd, as you would think there would be plenty of mirrors on the market since there's not a exactly a shortage of them in the human world. Then the villain shows off his collection of ten thousand mirrors and it all makes sense. Mirrors are rare and expensive because the villain is hoarding them all.
Forgetting for a moment that Cotton is just a plushie, one comes to the disturbing realization that Haruka returns to her world with the stitched-together corpse of her childhood friend.
