Charnel Invigoration

You mark up to 3 creatures within 5ft of you with a simple rune, healing the marked creature for 2d6+spell level. In addition, the marked creature gains bonus hit points equal to twice their CON modifier and lose all levels of exhaustion while you maintain concentration from being imbued with the energies of the undead. At the end of the spell's duration, or when concentration is broken, the marked creatures suffer 1 level of exhaustion, regain all lost levels of exhaustion, and take damage equal to the bonus health gained. 

When cast at higher levels you may mark 1 additional creature per spell level.

When cast at 6th level, all marked creatures temporarily gain 1d6 Strength for the duration of the spell. At the end of the effect or when concentration is broken, the creatures temporarily have their Strength reduced by the same amount for 1 hour. This effect can be ended early by the use of a Greater Restoration spell or similar effect.

When cast at 9th level the marked creature gains 2d6 Strength and 1d8 Constitution for the duration of the spell. At the end of the effect or when concentration is broken, the creatures temporarily have their Strength and Constitution reduced by the same amount for 1 hour. This effect can be ended early by the use of a Greater Restoration spell or similar effect.