Hi.. this is called 'geographic tongue'. You'll be relieved to know that geographic tongue is a harmless, benign condition that isn't linked to any infection or cancer. Two other names for geographic tongue are benign migratory glossitis and erythema migrans. In most cases, any pain or discomfort will get better without treatment. But if you have severe, ongoing pain, medication can help. These are examples of what your doctor or dentist may prescribe: -Over-the-counter pain relievers -Anti-inflammatories -Mouth rinses with anesthetic -Corticosteroids applied directly on the                          tongue -Zinc supplements

The details given by Dr Rao is pretty much it to your condition. Only thing I would like to add is to go to an Oral Medicine ( a dentist who has specialises in field of oral medicine) rather than going to a general dentist for such a condition