My son age of 5.5 years old is suffering from toothache (upper gum) and now swelling on cheek. which toothache has cavity form early, so is serious?

See DDS: See your dentist or pedodontist to treat the area of decay. Swelling is already present so time is of the essence.

See a dentist: You will need to take your son to see a dentist as soon as possible. He appears to have an abscess which needs to be immediately treated.

Very serious: Your son has a raging infection that is invading surrounding tissues. Your son needs immediate professional help. Call Dentist or specialist Pediatric Dentist. Do not delay.