How long does it take for a fever to come down in infants? My boy is almost 5 months old, we took him to the hospital yesterday as he had fever and was very dull. Doctor prescribed medication including paracetamol. It has been 6 hours since I last gave him paracetamol but his fever is still on the higher side, goes up to 102. The doctor said it is because he has cold but I am concerned that his fever is not going down yet.