Costly Heal

You heal a friend at the cost of yourself. Choose a friendly creature (excluding yourself) within range, which is healed 1d6 hit points. You take 1d4 necrotic damage, which can only be healed by taking a short or long rest.

The healing increases by 1d6 and the damage increases by 1d4 at 5th level (2d6, 2d4), 11th level (3d6, 3d4), and 17th level (4d6, 4d4)