There isn't sufficient information to suggest a specific diagnosis. But he may be developing a lower respiratory tract infection for which he would require antibiotics, antacids, antihistamines, antipyretic and cough syrup. I would advise you to take him to the ER so that he can be examined and undergo investigations such as CBC, X-Ray, etc to find the underlying cause and have it treated accordingly. These following steps may help: - Avoid cold food and water, preferably have hot food and water - Don't skip meals have a liquid diet containing soups and progressively increase to solid diet as per how you can tolerate. - Have food rich in vitamin C such as oranges to help build immunity. - Drink plenty of fluids, drink 3 liters of water per day - Do salt water gargling with lukewarm water thrice a day - Do steam inhalation (plain steam) thrice a day and apply vaporub over your chest and nose - Maintain good personal hygiene - Rest plenty, body heals while at rest If the condition persists or worsens visit nearest ER at earliest