Transfusion

Starting at the 3rd level, as an action, you may sacrifice a hit die to heal a willing target for the amount sacrificed plus your constitution modifier. You gain a number of temporary hit points equal to the amount sacrificed for 1d4+1 minutes. In addition, you may also sacrifice a spell slot to add that many additional dies to the effect (i.e. a level 2 slot will add two more worth of hit die to the healing effect) You may do this a number of times per day equal to you proficiency bonus.