Final answer:
The nurse should ask Mandi if any of her moles have changed in size or appearance, as this could indicate skin cancer.
Step-by-step explanation:
The most important question for the nurse to ask Mandi is: 'Have any of your moles changed in size or appearance?' This is because changes in the size, shape, color, or appearance of a mole can indicate skin cancer. It is important to monitor and track any changes in moles to ensure early detection and treatment if necessary.
Learn more about Skin Cancer