Draining Kiss

Make a melee spell attack against a creature you can reach. If the target is charmed, this attack has advantage. On a hit, the target takes 3d10 necrotic damage. The caster is healed by an amount equal to the necrotic damage dealt. This spell does not break charms that specify the charm ends when the charmed creature takes damage. 

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the damage increases by 1d10 for each slot level above 4th.