You can cause wounds to stop bleeding and being knitting immediately, drawing on the body's own natural vitality to do so. The target you touch with this spell may immediately spend two hit dice as a Reaction, rolling them and adding his Constitution bonus to the result, gaining that many hit points.

At Higher Levels: When you cast this spell using a spell slot of 3rd level or higher, the target may spend one additional hit die for every spell level above 2nd.