@nyna Hello, The white layer is probably just an excess of bacteria and small pieces of dead cells that come off the inside of the mouth. A simple solution may be to increase your daily water intake to maintain the hydration of your mouth and a good salivary flow. If you are concerned then consulting a dentist would be the best idea. As you said the white layer is on the roof then it might be a fungal infection. Creamy white lesions on your tongue, inner cheeks, and sometimes on the roof of your mouth, gums, and tonsils are the symptom. Please visit a doctor.