There is a possibility that you may lose your fingernails during treatment, so your approach with your nails should be as conservative as possible. This is the time to have simple, filed nails. A little nail color is okay, but layering on the glue or other adhesives that often damage even healthy nails is not a good idea.
If you are a fan of manicures and pedicures, cancer does not mean you need to stop these little pleasures. However, do take great care!