White coloured patches on tongue could be due to multiple reasons. varying from fungal infections to stress related oral manifestations of skin diseases to tobacco chewing or smoking habit related leukoplakia lesions. It is best to visit a dentist and get the cause diagnosed to avoid disease progression.

The description that you have mentioned is too brief and slightly vague to arrive at a diagnosis. A proper clinical examination by a dentist, preferably and oral pathologist or an oral medicine specialist will be required for a rational diagnosis. The right treatment can be suggested after a right diagnosis. Alternatively, you can post a good quality clinical photograph on Practo for an online consultation with a specialist. A detailed clinical history including any medications or habits like tobacco usage will also we required. White patches can be of different categories and the basic minimum requirement will be having a look at the photograph of the lesion. The least you can do at this point is brushing your teeth with your toothbrush every time after you brush your teeth. Do not use a metal or plastic or wooden tongue cleaner. Regards.