Uncontrolled Growth

You send a burst of healing energy so overwhelming that small plants sprout along its path to the target.  When it comes into contact with the target Creature the Creature regains 10D8 Hit points.  If a creature regains more then their maximum Hit Points Cancerous Growths begin to appear on their bodies and they must make a Constitution Saving Throw. 

On a failed save they suffer 6d6 Necrotic Damage as well as a point of exhaustion and at the end of each turn it suffers an additional 2d6 Necrotic damage and an additional point of Exhaustion. Upon Success the creature suffers Half damage and takes no points of Exhaustion. They can make another Saving throw at the end of each of its turns, before the effects take place. Once successful the creature stops taking damage and doesn't gain additional exhaustion. If Concentration is lost, the spell ends.

If cast at a higher level, add 1d8 to the healing per level and 1d6 of Necrotic damage per level above 5th.

The Exhaustion is caused by the growths on the creatures body, these can only be removed by a spell of 5th level or higher that cures diseases or other ailments.(For the purposes of immunity this is not a disease.) One usage of the spell Greater Restoration, Heal, or other such spell will remove all growths and remove all the points of exhaustion incurred by this spell.