It looks like geographic tongue... Resolves on its own...As long as not painful no need to worry...For further info pls Google geographic tongue.

This is a condition known as Geographic Tongue, it’s benign, painless and non irritating. This happens for some unknown reasons. These patches (lesions) give the tongue a maplike, or geographic, appearance. The lesions often heal in one area and then move (migrate) to a different part of your tongue. Geographic tongue is also known as benign migratory glossitis. Although geographic tongue may look alarming, it doesn't cause health problems and isn't associated with infection or cancer. Geographic tongue can sometimes cause tongue discomfort and increased sensitivity to certain substances, such as spices or salt Symptoms Signs and symptoms of geographic tongue may include: Smooth, red, irregularly shaped patches (lesions) on the top or side of your tongue Frequent changes in the location, size and shape of lesions Discomfort, pain or burning sensation in some cases, most often related to eating spicy or acidic foods Many people with geographic tongue have no symptoms. Geographic tongue can continue for days, months or years. The problem often resolves on its own but may appear again at a later time.