Panel 1: We fast-forward to the night of the dance. As Mike gets ready to head out, we find him wearing a track suit as if he intends to wear a Sioux war bonnet, break dance and sing acid jazz songs about the robot apocalypse. This alarms Elly who, having questioned his choice of attire for the dance, tells him to change. Since Mike is stupid and has a ridiculous motivation for dressing down, he sputters out "But...." instead of the more usual "UH?"
Panel 2: Elly's doing that "turn her back to him and close her eyes as she gets all snooty and pious" bit of hers means that she doesn't see that he's scowling with rage when she tells him to put on a nice shirt and good pair of pants because the girls won't dance with him looking like he doesn't care what people think of him. She's right about that but what she doesn't know is that the moron thinks that all the girls ever are laughing at him because of Allyson and Martha in order to avoid the realization that most people think of him as Anonymous Slouching Imbecile Number 5.
Panel 3: When she asks if he brushed his teeth and remembered the deodorant, he bellows "MOM!!!" like a Peanuts character.
Panel 4: He scowls in rage because he should have told her that he was going bowling.
Summary: It seems to me that Mike should have been dressed to the nines without Elly prodding him. Just as Gordon should be eager to go to the dance to see if he can wheedle a dance out of Allyson, Mike should be trying to actively enrage Martha instead of passively whining that some day, she'll be sorry she 'mistreated' him. If only he had a brain and acted like a normal boy instead of an oblivious coed who couldn't be arsed to get her facts straight.