Potion, uncommon
You regain 1d4+1 levels worth of spell slots when you drink this potion. The potion's blue liquid glimmers when agitated.
When using this type of potion for every 5 levels of spells regained the user will incur 1 point of exhaustion. This effect is cumulative with other potions of this type.
Notes: Healing, Utility, Consumable
Dude, I had literally this EXACT idea. Good implementation.