TFPH - Blood Storm

At your command the sky weeps tears of blood.

Blood rains down from the sky in a 80 foot wide square centered on a location you can see within range. The space within this squarr is considered difficult terrain. All creatures within the area must make a Constitution saving throw against your spell save DC. On a failure, a creature takes 5d12 necrotic damage and suffers one wound. On a success, the creature takes half as much damage and suffers one wound. 

While within the area a creature suffers one additional wound at the start of its turn, and suffers one additional wound when moving into the area for the first time on its turn. A creature can have no more than 5 wounds. When not in the area, a creature removes one wound at the beginning of its turn. A creature suffers 1d12 damage for each wound it has at the end of its turn.

A wounded creature may use an action to make a medicine check to remove it's wounds, or another creature may use an action to make a medicine check to remove the wounds from a wounded creature. The number of wounds recovered depends on the result of the medicine check, a result of 9 or lower does not remove any wounds, 10-14 removes 1 wound, 15-19 removes 2 wounds, 20-24 removes 3 wounds, 25+ removes all wounds.