Yeah, I meant he would only lose the health he gained, if he had already lost it there would be no change.Wait, what?
Let's run this through.
Markus has 4 health.
He uses Living Pain, buffing his health by 2.
He now has 6 health.
He takes two damage during the buff.
He now has 4 health.
The buff ends, removing the +2 to his health.
He has 2 health - exactly the same as if he never used the buff.
The only utility currently is if he's on low health it might buy one more turn in which he could be healed, but other than that it is quite literally a waste of a turn and of MgS.