How does Charlie get into trouble during his music class in the book, Lemonade Mouth: Adapted Movie Tie-in Edition?

Charlie is dreaming about a girl in his class called Mo when a spitball fired into his hair wakes him up. Seeing the teacher paying no attention, he decides, for once in his life, to get his own back and fires a spit ball back at who he thinks is the culprit - Scott Pickett. Unfortunately, the spitball misses Scott and hits Mo. Her subsequent screaming draws the attention of the teacher Mrs. Reznik.