Hi.. Can understand your concern.. As per your complain the white patch on the tongue can be due to yeast infection known as THRUSH or CANDIDIASIS which leads to formation of cheesy white patch on the surface of tongue and it can also involve other mucous membranes like gums, inner cheeks,inner lips etc.. The dryness of tongue and inflammation of papillae also occurs due to the fungal infection.. It may be due to a number of reasons like POOR ORAL HYGIENE,LONG TERM USE OF ANTIBIOTICS AND STEROIDS, PREGNANCY, IMMUNOCOMPROMISED CONDITIONS LIKE HIV,UNCONTROLLED DIABETES,DRY MOUTH etc.. I would suggest you to consult a dentist and get a clinical evaluation done and as it has a characteristic pattern of clinical presentation it can be easily diagnosed.. In case if thrush is diagnosed you have to take oral anti fungal drugs like FLUCONAZOLE and ITRACONAZOLE along with NYSTATIN mouthwash and antifungal lozenges.. Maintain a good oral hygiene.. Frequent intake of Probiotics like Yoghurt and garlc can help.. Do salt water rinses.. Avoid antimicrobial mouthwashes as it can further be having a deleterious effect on the clearing of the infection and can cause increase in infection.. Drink plenty of water to prevent dry mouth and maintain hydration.. Hope this information helps.. If you find the answer helpful kindly write a positive review and click on found this answer helpful as a token of appreciation.. Thanks and regards.. Dr.Honey Nandwani Arora..