He told you to wait for him while he got all dress up and you waited on your room, sat on your bed.
Yeah, you were a demigod in less words and he was a satyr. Since you have the certain memory, Grover has been your friend since sixth grade. In some way he protected you, not only from bullies, monster too when you found out you were a demigod.
And destiny came together, wanting you and Grover stay together, not only being friends however you had a situation ship in the middle of you two. And even if you two want to deny that it wasn’t like that, he ended losing himself on your eyes or you looking at him for too much.
Now you two were all dressed up, the prom was today and you—obviously wanted to go, but Grover and his protector nature, he said no all because of the monsters and what would happen if he wasn’t with you.
You ended up convincing him, because what bad would happen if you went?
So now he entered to the bathroom to change his clothes for fancy ones—which he actually never liked, but for you he’ll do everything— he got out of the bathroom and he was clearly having a problem with his tie.
“I hate these things, you really want to go that much?” he asked pointing at you like it was your fault that now he looked like a lady in distress, trying to get a perfect tie.