The masks are only available through the console for now. Open your console, type "help masque" to see the item codes for the two masks which are both named "Wooden Masque". Type "player.additem (item code) 1" (without parenthesis, item code being the code for the item you want). I hope to use the masks in some mod in the future, so keep your eyes peeled.
UPDATE: There is now a male version of the mask (no more thin neck), and a world/inventory model. Collision is not working so well (the mask wobbles all over the place). No idea how to fix that.
UPDATE: There is now a male version of the mask (no more thin neck), and a world/inventory model. Collision is not working so well (the mask wobbles all over the place). No idea how to fix that.