Hi, Welcome to Healthcare Magic Forum.
May be your son is having Sinusitis
or Upper Respiratory Infection
. Since how long does he have this Problem? In any case, he needs antibiotics, take him to a Pediatrician
for further evaluation. Give him steam inhalation twice to thrice daily and let him sleep with head end elevated (Keep an extra pillow below his head). Let him take plenty of rest and plenty of fluids in form of water or fruit juices. Encourage him to rinse out his nasal passages and apply warm compresses to his face around eyes, nose and cheeks.