Why did Scout wear her pork costume on the way home in Chapter 28?

Scout decided to keep her ham costume on after the show in
order to "hide my mortification under it." Scout had missed her cue during the show, and
Mrs. Merriweather had to call out "Pork!" at least three times before Scout finally made
her very late entrance. Her appearance was apparently so hilarious that Judge Taylor had
to leave the auditorium; he was "slapping his knees so hard" that his wife had to bring
him some water and one of his pills. It's a lucky thing that Scout kept on her chicken
mesh costume, because it proved to be the insulation that saved her from the slashing
knife wielded later by Bob Ewell.