Most fevers in children are viral in origin and take 3-7 days to subside completely,just give paracetamol for fever and repeat every 4 hours if required. If mild,just give steam inhalations for cold and cough and decongestant nasal drops for nasal block or increased cough on lying down. If not improving OR accompanied by other symptoms like vomiting or loose motions or coughing and breathlessness or dullness and refusal to feed,consult your paediatrician.