Hi.. Thanks for contacting HCM with a health query.. You have low grade fever,epigastric pain,coated tongue.. I first want to consider enteric fever. Next is a viral fever with gastritis.. If I happen to have a patient like this in my outpatient department I would order for total White cell count ,take up testing for typhoid and treat accordingly with broad spectrum antibiotic,anti pyretics and anti ulcer drugs. You meet a doctor in person and get investigated and treated because it is little chronic. As a measure at home you take plenty of replenishing liquid diet like fruit juices and rice gruel,sponge with tap water (neither hot nor cold)