The free DLC Fox Mask is now working on Steam.
This mask is given away via the loyalty program of BANDAI NAMCO Europe (http://bnent.eu/LittleNightmaresFreeDLC)
An issue with the code prevented the Fox Mask to unlock in the game for people who redeemed it between May 3rd and May 4th.
If you previously redeemed the code, the fix will automatically apply when you launch the game. Check the 'Extras' menu to see the masks currently availabel and activate the one you want to wear.
Enjoy the game and don't forget tjo hug the Nomes