ozone through ear clears the infections due to viruses, bacteria, etc. The ozone gas actually gets into the brain, eyes, forhead area too. Once you start doing on your son, he will start feeling the benefits not only on his ears but also as clarity of mind, eyes more clear, etc. A 4year child cannot probably recognize or even if he recognizes, may be he cannot express well. when you do this continously, you will see the benefits in the long term too. Also, sometimes my ears get blocked and i use ear wax drops (OTC from any pharmacy) and it opens up. i am not a doctor either, just my experinces. hope this helps.