Benign Migratory Glossitis aka Geographic Tongue is a harmless condition in which the tongue has areas of darker pink patches. What is actually occurring is the papilla on the tongue disappear, rearing sensitive areas to acidic foods and drinks. According to Web MD, "Affecting about 1% to 3% of people, geographic tongue can show up at any age. However, it tends to affect middle-aged or older adults more often. It appears to be more common in women than in men. Geographic tongue is the name of a condition that gets its name from its map-like appearance on the upper surface and sides of the tongue. It may occur in other areas of your mouth, as well".
If you suspect you have Geographic Tongue consult with your physician or dentist.