Well, I'm pretty sure that last resort can only be used if all other moves during the current switch-in have been use at least once, you could use sketch first turn, take the hit and I believe it will power up your last resort You may also just carry last resort and nothing else, as I believe it will be powered up, as all other available moves (or lack thereof, in this case) have been used. Very good question, I'll Try My best to do some definitive research, as this is just going off of assumptions based of my knowledge of the game.
Hope this helped!
