Is he coughing anything up? What color is any nasal drainage? Do not try cough medicines. Stick with an expectorant if you do to break up the mucous-not to supress it.
It hasn't been that long, so I wouldn't worry about it provided there is no high fever.
"Eucalyptus and lavender oil. Add only one drop of each of these to a facial steamer, pot of hot water or some vaporizers. They can help clear up the congestion faster.
Vapor rubs on the chest. Occasionally, these can cause wheezing because the vapors may be too strong for some children, but overall they will work well. It is safe to try, but do observe your child to make sure it doesn't cause wheezing.
Drink twice as much liquid. This will help to thin secretions and prevent dehydration."
"Only use medication when the symptoms are interfering with your child's daily life or keeping them, or you, awake at night. It's okay to let your child cough several times an hour during the day. It is better for her to cough up the mucus so it doesn't sit in her lungs. It is also better to tolerate a runny nose or some nasal congestion during the day if it isn't bothering your child.
Treat your child's specific symptoms. If your child simply has a bad cough, but no nasal congestion, then you don't need a fancy combination cough and cold medicine. You simply need a cough suppressant. Here are the four major types of cold medicine: "http://www.askdrsears.com/html/8/t089800.asphttp://www.askdrsears.com/html/8/T081000.asp