Have a quite word with her, with no witnesses, and explain in a very professional manner “I appreciate your concern, but kindly fuck off and die”.
When you have your meeting with the head, if its not a work phone, then there is no proof so nothing to worry about. Should only be a quick conversation mate as there is no proof and as long as she has not put a formal complaint in and an investigation procedure instigated there is nothing to worry about. Don’t stress over it and enjoy your weekend.