I lost a "Refill Heart" after failing a lesson, despite not having used it. Help?
Once you choose "Heart Refill" in lesson, it is considered used whether you end up needing it or not. So, think carefully before you choose to equip it. Here are some replacement lingots. :)
EDIT: Clarification, you can still purchase it in the store and hold onto it for a while. It isn't considered used until you are in a lesson and specifically tell it to "Heart Refill"