The fever is your body's way of trying to heal or recover and most fevers go away on their own after a few days.  A fever can be brought down by the  right kind of treatment. Drink plenty of fluids and rest. Taking medication is not necessary, but it may increase your comfort level. Use an over-the-counter fever reducer like aspirin or ibuprofen.  Call your doctor if your symptoms last more than 3 days and/or more severe symptoms develop. Children and teens should not take aspirin as it is linked to a condition called Reyes’ disease.  As well, if your child has a temperature under 102 degrees Fahrenheit (38.9 degrees Celsius), they can likely be treated at home. Visit the doctor if the fever persists over 3 days and/or more severe symptoms develop.

How would you rephrase that briefly using Vietnamese?
Xử lý sốt tại nhà nếu sốt dưới 39,5 độ C và người bệnh trên 18 tuổi. Điều trị sốt bằng cách cho trẻ uống nhiều chất lỏng và nghỉ ngơi nếu trẻ không có biểu hiện các triệu chứng nghiêm trọng.