Arcane Blood Ring

While attuned to this ring, once per long rest as an action you can take necrotic damage equal to your level. When you do, you can choose expended spell slots to recover. The spell slots can have a combined level that is equal to or less than half your level (rounded up), and none of the slots can be 6th level or higher.

You can also, as an action, expend an available spell slot in order to regain a number of hit points equal to twice the level of the spell slots you expended.