hello, You may have an opportunistic fungal infection in your mouth. The prescription Nystatin is used to treat an oral yeast infection. Common complaints include red, burning tissue, coating on your tongue and altered taste. Taking Acidophilus or probiotics can help prevent this . Your medical history can be harsh on oral tissue. Give your tissue a chance to return to normal by keeping well hydrated, continue with a bland diet, proper balanced vitamis with attention to adequate vitamin B12 and avoid irritants. Limit alcohol and smoking. Keep up to date with your dental exam and cleaning. Check for any untreated dental problems and practice good dental daily care. Report any medications with side effects and be aware dry mouth is a common occurance that can contribute to your symptoms. Thank you for your inquiry.