On the basis that Hit Points are the ability to keep going and reflect an abstract will or morale as much as anything else (an idea explored a number of places - for instance, here), witness the following, designed to get the player up and moving when the healing potions aren't to hand.
Dwarven Mustard: Great Serpents of Smoke, that’s strong! Make a body save or lose the beneficial effects (subject either chokes it down or spits it out, depending on nearness of lost body save). If save made, 1d6 HP.
Elven leaves: a fine remedy; regain 1d6 but spend a round contemplating the taste and aftertaste of these most aesthetically pleasing of medicines.
Satyr Vintage: Like really potent retsina. A draught will restore 1d8 HP, but player must make a Body Save to get over the taste....and a Mind save, or Charge/Retreat as per spell card.
Dodgy Nostrum from Dodgy Apothecary: You bought it from a booth at a fairground, or a dusty shop in a back alley. How does it help/hinder?
Roll 1d6: 1. make body save, or become incapacitated with stomach cramps.
2. Make body save, or lose 1d3 HP
3 . Make body save, or lose a turn.
5. 1d3 Hp
6. 1d4 Hp