Alright fair, tapped it with a berf (max HP increase 10 HP -> 8 HP, given poison counters 6 -> 4).
When I first thought of this idea, I was trying to limit its applicability as a long-term heal. Thinking about it now, its initial break-even time of 5 turns limited its applicability as a self-heal too much even over the course of short games. Pushing it out to 8 turns should make it better for self-healing, while still letting its long-term effects play out in practice.