People mess up all the time. And often it's mostly the person involved who is most put out by it. 90% of the time nobody else even notices.
This is true in life, but also in gaming. If you're running a game, don't sweat trying to be perfect. Every GM makes mistakes, or forgets rules or worldbuilding story or whatever. And usually it's only the GM who even notices or cares. Your players won't notice or care most of the time. And it's only a game after all. You don't have to be flawless - players will realise that you're human and occasional errors can happen. If they do notice, you can simply acknowledge it as a mistake and move on. Worrying about being perfect shouldn't ruin the fun of the game.
Commentary by memnarch (who has not seen the movie)
Sounds like Pete's having a recital of some kind! That will likely go well, especially with the support from Ben and the cover from Sally. I wonder if he's picked up an instrument or is singing. I also wonder where he might be performing that he feels the need for cover; unless it's an obvious miss or these strangers are musicians/singers as well, it really shouldn't be that noticeable. It's easy to forget sometimes that everyone has different skills and perspectives, which also ties in well with Pete's complaint in the previous comic about things being obvious for how to take over the world.
Transcript
Chewbacca: And you’re inviting me because...?
Rey: It’s with a bunch of strangers! You know I’m used to being hypercompetent.
Chewbacca: ... You need moral support.
Rey: And if you pretend to mess up a few times, it’ll take the heat off me.
Chewbacca: Honestly, nobody’s going to care if you drop a beat here or there.
Kylo Ren: That’s what he tells his kids, but...
Rey: See? Sally agrees.
Kylo Ren: I think I’ll join too! I can sing.
Chewbacca: Okay, that really will cover any inadequacies in the instrumentation.
Kylo Ren: Hey!