Potion of Regeneration

This is a black liquid with green swirls, is concocted from the blood of a troll and several other secret ingredients. It's smell has been compared to rotted meat. As an action a creature may drink a dose of the elixir (or administer it to another creature). The creature that drinks it must make on a DC 12 Constitution saving throw.   On a successful save, the drinker regains 10 hit points, up to their hit point maximum. In addition, any limbs severed from the character can be reattached, simply by holding the two ends of the severed limb together (this takes an action, either by the character or an ally). This saving throw is repeated at the beginning of each of the drinker's turns until it either fails the save or 1 minute passes. If a 20 is rolled on the die when making the save, the damage is still healed, but the healed flesh looks like troll skin.   On a failed save, the drinker adds one level of exhaustion and that dose of elixir is neutralized, having no further effect (good or ill).   Each vial holds 3 doses. If more than one dose of the elixir is drunk within 24 hours, these saves are made with disadvantage. If a character takes two doses of the elixir within 1 hour of each other, the character will automatically fail the save and gain two levels of exhaustion.   The elixir has no effect on the dead, constructs, or undead, and it cannot regenerate damage from acid or fire.