Cursed Regeneration

Upon getting this tattoo all your wounds heal miraculously, even missing limbs or organs will regrow, and any disease afflicting you will be cured. In addition At the start of each of your turns, if you have no more than half of your hit points left, you regain 8 hit points. You don't gain this benefit if you have 0 hit points. Each time you heal 20 hit points this way, you gain one temporary madness. When you have 2 of them, you gain one long-term madness. A long-term madness gained in such a way can only be cured by a wish spell or greater restoration cast at the 9th level. When you have accumulated 3 long-term madness, you fall under the complete control of the Deep one.