Why is my geographic tongue changing color? i've had a case of geographic tongue for a while now, with the usual red patches. lately, they seem to be turning a whitish color. does this mean the patches are healing?

Geographic : Geographic tongue is also known as benign migratory glossitis. The red areas are missing papillae. In a way you can say that is is healing, but other areas may now become red. Please see below link for a more detailed explanation.

I : I totally agree with doc...The tongue is mainly composed of muscles. It is covered with a mucous membrane. Small bumps (papillae) cover the upper surface of the tongue. Between the papillae are the taste buds, which allow you to taste. The tongue moves food to help you chew and swallow. The tongue also helps you form words. There are many different reasons for changes in the tongue's function and appearance. Color changes may occur with inflammation of the tongue (glossitis). Papillae are lost, causing the tongue to appear smooth. Geographic tongue is a patchy form of glossitis where the location of inflammation and the appearance of the tongue change from day to day. Sometimes the upper surface of the tongue turns black or brown in color. This is an unsightly condition but is not harmful. Minor infections or irritations are the most common cause of tongue soreness. Injury, such as biting the tongue, can cause painful sores. Heavy smoking will irritate the tongue and make it painful, which may also change it color. Normally geographic tongue doesnt just "heal". If your truly concerned see your dentist and have them take a look at it. Good luck!