I'm a Slytherin. I help my friends and housemates first. And I don't think my dear friend would appreciate it if I undermined his efforts to succeed in our Lord's challenge for him.

So if you're a big girl then I'm sure you can find, all on your own, Essential Stagecraft Illusions in the library. It's by Alvin Valore.

You want the "luxury locks" glamour. It makes it appear as if you have hair, but there's actually nothing there.