I'm a bit stuck here, because you generally shouldn't have "it just doesn't work" as a consequence for failure, because then the players can just try the exact same thing again. But Guide and Comfort should typically happen in situations where there aren't many threats or opportunities for complications, and it seems overly harsh in this sort of game to mark fatigue or a condition when trying to clear fatigue or a condition. All I can think of is that it takes time, and removes the opportunity - eg you can't do the same Move until the situation has changed again, because you've fumbled the social situation.

But what other things could happen on a fail, that fit the fiction, and the general tone of the game?