| Temporary hit points and real hit points don't blend together. But as for if you are at negative, if you had 9 hit points in the shape of a troll, it doesn't matter what happens at the end of the spell.
Temporary hit points apply to current hit points. Polymorph hit points apply to MAX hit points.
So if you went in at 20 / 40 per say, and "rested for a night" with polymorph brings you up to 27 / 80, and you take 7 points of damage during the polymorph (bringing you right back down to 20), then you stay at 20 when the spell ends and your maximum hit points becomes 40 again, instead of 80.
This is because it's a spell effect, not a natural effect where constitution would affect both current and maximum hit points. Although, you will lose current hit points if your MAX hit points goes below your current hit points.
If a spell effect turns your hit points from 30 / 40 to 30 / 25, then your hit points are 25 / 25 UNLESS it specifically states you have temporary hit points, which polymorph says it does, so in that case you could essentially have current hit points equal to your caster level above your max.
Polymorph is by far one of the most confusing spells in the game, and I wish they would make it just a wee bit simpler, but that aint gonna happen anytime soon. |