Yes, the moment where she stops moving forward is the “event.”
certainly no fists or teeth and she is never on the ground, but that poster seems to be mixing up some other assaults on press at other Trump events with this one. She never says she was on the ground in her complaint.
She does abruptly change direction. It is not inconsistent with being pulled physically backward, and some people do bruise from something as light as being grabbed and yanked.
I’d say she got grabbed and yanked, but that it’s a big stretch to call that an assault.