I just stared the game and I have already collected some heads and skin for my character. I cant figure out how to actually use the head/skin. When i go to a vendor and go to the "sell" option, I can see the head and skins and it says "Unlocks this head for the quick change system when used from inside your inventory". I have gone to the quick change machine and I didn't see the head, and when I go into my inventory, I cant find the head. So i'm not sure how to unlock it from inside my inventory.