Vampiric Withering

Up to four creatures within range  make a Constitution saving throw. On a failed save the creatures take 3d8 Necrotic damage, or half as much on a successful saving throw. Until the end of your next turn you may touch a creature and use an action to heal that creature for half the total damage dealt. If you do not heal a creature this way, you suffer that amount of Necrotic damage.

At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the damage increases by 1d8 for every 2 slot levels above 4th (4d8 at 6th level, 5d8 at 8th level).