A: I've had dead when trying to use it.

B: I need to have a spell AND a potion?? Where do I get the spell??

I think there's a spell. Might want to consult help to confirm. As for its potentially nonexistent whereabouts, where would you put a high level spell that can reanimate the once living as not zombies?

A mage tower, probably.

I always just reloaded if someone died as iirc dead drop their stuff to the ground and it was pain to re-equip everything every time someone died. Worse if you did not have the spells or balm to revive them as you'd have to pick up everything (might not be even possible with limit to number of items each character can carry. If it was random encounter, all stuff you could not take would be gone after exiting battle.), walk half way across averum to a healer to raise character, give him his stuff back, re-equip and then walk back half across averum to continue what ever you were doing.