Hi.. Can understand your concern.. As per your complain it seems that you have a condition known as DRY MOUTH and white tongue is due to fungal infection known as Thrush... Thrush can lead to dryness of mouth.. Along with it the the medications that you must be given by your surgeon like antibiotics can also cause side effects like nausea, tiredness and thrush is also caused by antibiotics as they destroy the good bacteria that resists infections from attacking the body along with harmful bacteria.. I would suggest you to consult your gynaecologist or surgeon and explain the immediate symptoms and get a clinical evaluation done.. In case of Thrush Oral antifungal medicines like Fluconazole and Itraconazole , Nystatin mouthwash and antifungal lozenges can help.. Along with it in case if you still take medicines reduction in dose or withdrawal of medicine can help in eliminating side effects.. Drink plenty of water to maintain hydration.. Adding Probiotics to diet like Yoghurt and garlic can help in clearing off the fungus... Hope this information helps.. Thanks and regards.. Dr.Honey Nandwani Arora..