Close Wounds

Touch an ally and channel their inner life force to cause a surge of natural healing. If they have at least 1 hit point, they can spend one of their own hit dice rolling the die and adding their constitution modifier to the roll and regaining that many hit points.

This spell’s healing increases when you reach certain levels. At 5th level, the healing is increased to 2 hit dice plus Con, and the number of hit dice is increased to 3 at 11th level, and to 4 at 17th level. If the Target only has 1 hit dice left but you are at level 5, they can still only use the number of hit dice they have left. You cannot use what you do not have.