The symptoms, ‘painful sore throat with fever blisters on the uvala, extreme fatigue, lack of hunger and thirst, strange taste in my mouth’ could be due to
gastric reflux even though the endoscopy is negative. Take a late night snack. Raise head end of bed. Take Omeprazole empty stomach in morning and an antacid gel at bedtime. Refrain from smoking, alcohol, fuzzy drinks, caffeine, and spicy food. Hope these tips help.