Hello, Common reasons include: -fungal condition such as Thrush -allergic reaction -mouth breathing with dry mouth -systemic reaction indicating disease or deficiency -side effect of medication -disease of the tongue Pleases be sure that you maintain proper nutrition, balanced vitamins and stay well hydrated. Good home dental care and routine dental exams are important. The mouth has a natural flora and an imbalance of bacteria can cause changes you describe. Acidophilus can help prevent or reestablish this balance. By prescription, your dentist may need to recommend Nystatin to treat an oral yeast infection. A dry mouth can cause a change in the surface of the tongue and a burning sensation. While you are aware of the discomfort you may try to produce more saliva or this extra saliva may be a reaction to the feeling oh something more in your mouth. Are you aware of grinding your teeth or mouth breathing at night? Stress can bring this on. Rinsing with warm salt water has a soothing and cleansing affect. Avoid spicy foods. Anti-inflammatory medications and an antihistamine such as Benedryl may help reduce signs of inflammation. A sinus infection with post nasal drip or acid reflx may cause more acid in the mouth. Irritants such as this, smoking or a sudden change in your habits could affect the tongue as you describe. Evaluate if you have made any changes in products used or diet that may be responsible for an allergic reaction. Stop the use and look for improvement. You may have trauma to the side of your tongue from it being in the way, pushing against your teeth or even biting the edge. any disturbance to the surface of the tongue may affect your taste buds. A dental exam would evaluate for abnormalities or growths. The back border of the tongue should be closely inspected for any suspicious changes to tissue that could be cancerous. A blood test can check the function of your organs and disclose deficiencies that may be responsible for some of these symptoms. Your over all health with conditions such as uncontrolled diabetes, gastric disorders or liver malfunction can be responsible for changes in the mouth. Thank you for your inquiry. I hope some of my suggestions help with a diagnosis. I would be glad to answer additional questions.