To dream of wearing a bandana across your face implies a fear of saying something that might give yourself away. You may feel as though you are in the wrong or inadequate in some way but that if you are careful about the things you say, no one ever needs to know who you truly are. Energy doesn't lie however, and a dream of a bandana is letting you know that you might as well be true as people will respond to your energy regardless of what you say or do.
Alternatively, dreaming of wearing a bandana as a type of head dress indicates a desire to stand out from the crowd and be noticed.