Hi.. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concerns.. As per your complain it seems that you have a fungal infection in mouth known as ORAL THRUSH or CANDIDIASIS due to which there is formation of thick yellowish layer on the surface of the tongue and the dry mouth is also due to thrush which is commonly seen in patients having thrush.. Due to infection there is inflammation of the taste buds leading to swollen appearance and at times there can be redness and pain.. You should consult an Oral Physician and get evaluated and a clinical examination is sufficient in case of Thrush due to a typical cheesy white to yellowish patches over the tongue and at times a microscopic examination of the small portion of patch can help in making the diagnosis.. If thrush is the final diagnosis the physician will advise you oral intake of anti-fungal medicines like FLUCONAZOLE or ITRACONAZOLE for 14 days. Nystatin mouthwash and anti-fungal lozenges will help.. Take more of probiotics like Yoghurt and garlic.. Drink plenty of water.. Warm saline gargles should be done as it will help in reducing the inflammation of circumvallate papilla.. You can also take saliva substitutes [artificial saliva] for lubricating mouth. Hope this information helps.. Thanks and regards.. Dr.Honey Nandwani Arora..