Yesterday's altercation is the latest in a series of confrontations that have marred recent Trump events.
The girl told police she punched a man who groped her, and another man then pepper-sprayed her, Janesville Police Sgt Aaron Ellis said today. The girl and a 19-year-old woman standing next to her were treated and released from a hospital, police said.
Ellis said the girl could face charges for punching the man, identified by the Wisconsin State Journal as Dan Crandall.
Crandall said someone standing behind him used the pepper spray. That person could be charged with illegal discharge of pepper spray since he was not using it in self-defense, Ellis said.
"It doesn't appear that he was directly involved," he said.