Since she is your parent's guest, I would definitely allow them to make restitution to you.
The term Pioneer does not mean mature seasoned Christ-like personality.
Just about anybody baptized can pioneer, whether they are sane or not, pschologically balanced or not, on psycho meds or not. Just yesterday at the meeting they spoke of a sister who complained of being depressed and the recommendation was for her to Pioneer!!!
So, Stilla, come on! Dont be too quickly thrown from your horse by this one. The old fashion art of hosting meant that the guest was entitled to feel at home and that meant sharing your resources as needed.
People will always be people. People will always dissappoint you. It is not people we are worshipping anyway.
Get your parents to shell out for the beauty creme and learn a lesson.