My mother has made another doctor's appointment in secret. What should I do?

I am confused about what I should do. Since last December my mother has complained of itching. We went to her PCP two or three times and a dermatologist once. They told her nothing was wrong and told her to use hydrocortisone creme. She also had some feminine itching, so she made an appointment with a gynecologist, who found nothing wrong and prescribed a hydrocortisone creme. For the last two weeks she has been wanting to go to the doctor again for her itching. I told her we had gone several times and I wouldn't take her again. She denied even going to the doctor, though I don't think she believes her denials. My mother loves to visit doctors.

This evening we received a recorded call from the dermatologists office to confirm the appointment on Friday. I don't know what to do. I haven't mentioned it to her. I know she will expect me to take her even after I told her I wouldn't. I know it is a waste of our time and Medicare dollars.

I haven't mentioned to her that I know yet, because I haven't decided what I should do. I thought I would ask what the people here would do. I dread another battle, but I am embarrassed to keep running to the doctors when they can't help.