Hi, Welcome to HCM Sores in mouth can result due to varied reasons like infection, irritation, food allergy, apthous ulcers, canker sores,stress, low immune system, vitamin deficiency, etc. 1. Take food rich in minerals like zinc, iron and folic acid, they will boost up your immune system and check infection spread. 2. Vitamim B deficiency may be the cause of your ailment, take vitamin B supplements and food rich in Vitamin B complex like pistachio, hazalnuta, wheat and rice ( with bran ), corn, veggies, garlic, dried spices, cheese, eggs, liver. 3. Keep yourself well hydrated. 4. Avoid eating spicy abrasive or acidic food. 5. Take care while brushing or flossing your teeth. 6. Use medicated mouth wash 2-3 times a day after each meal, use medicated mouth gels over the sores for relief ( hexigel oitment for oral use ). 7. For pain you can take analgesics or acitaminophen ( Tylenol ), get clinically assessed you may need antibiotics. 8. Take semi solid food like porridge, etc. Take care.