Close Wound

You touch one willing creature and temporarily accelerate its natural healing. If the target has at least 1 hit point, it can spend one of its Hit Dice, rolling the die and adding their Constitution modifier to the result. They regain hit points equal to the total (minimum of 0).

The number of Hit Dice a creature targeted by this spell can spend increases by 1 when you reach 5th level (up to 2 dice), 11th level (up to 3 dice), and 17th level (up to 4 dice).