The reddish areas may be slightly tender. They have an irregular shape and are usually surrounded by a white border. In this type of glossitis, the reddish areas can resemble a map. That's why it's also known as geographic tongue. Another name for it is erythema migrans.
Geographic tongue will disappear and reappear in different places on the tongue. The pattern may change very rapidly. These quick changes occur when you lose some of the tiny, finger-like bumps, called papillae, on your tongue. This creates flat areas that can last for more than a month. Geographic tongue may also appear, rarely, on other surfaces of your mouth, such as inside the cheeks.