Hello, Body temperature varies throughout the day, low in the morning and high in late afternoon and evening. In this case, the patient had a cold and cough about a month ago, which has cleared at the moment, but the fever still persists every evening till night. So the causes of fever could be bacterial infections, viral infections, pneumonia, bone infections, appendicitis, TB, skin infections, meningitis, sore throat, cold or flu like illness, ear infections, sinus infections, infectious mononucleosis, bronchitis, urinary tract infections, bacterial and viral gastroenteritis, autoimmune inflammatory disorders, Hodgkin's disease, Non- Hodgkin's lymphoma and leukemia, thrombophlebitis and medications and pyrexia of unknown origin. If the fever is mild, you don't need any treatment. Drink fluids and rest. But, if the fever is more than 39 degree celcuis or higher then you should search for associated features. Complications may include severe hydration, hallucinations. Hence a proper history from the patient, a detailed physical examination with laboratory investigations and treatment depends on the type or cause of fever. In the mean time the patient can take rest, plenty of fluids, and paracetamol for the time being and assurance to the patient. You can also consult your physician for the same. Thank you.