Does the Recovery power only heal physical stress and not mental? Is there a way to heal mental stress besides taking a consequence?
All stress tracks (not just Mental) clear after a conflict ends. Unless you take consequences, which don't "heal" stress, but more absorb it, all your stress returns as soon as the conflict ends, as long as there's a reasonable opportunity to stop and take a breather.
It is possible to dive right from one conflict to another without a chance to rest. Just defeating a bad guy or whatever is not enough to trigger stress recovery. When wizards in my game are going from conflict to conflict with short rests, I try to decide if they have had enough time to unwind in between. I ask myself, "Is this next conflict a continuous event emotionally? Has there been another state of mind in between?"
I will have to check my book for the exact details on the Recovery power, but if memory serves, it's about Physical attributes, like Toughness and Might are.