While we're not sure where this chapter takes place, we can assume it's at the performance at the Palace based on how the Mad Dog Fan Club, composed of dozens of lovesick teenage girls, is out in droves.
The Mad Dog Fan Club asks him how he got his name. Mad Dog says that when he was two, he would bite anything he could get his hands on, including people—ouch—so his dad gave him the nickname then, and it stuck.
Later on Billie Jo asks Daddy what Mad Dog's real name is. He looks at her like she's nuts though, and Billie Jo imagines that Ma would have told her the truth.