So sorry to hear about this persistent cough, and am glad that you have been working with your doctor
to help with this problem. There are so many possible explanations for a cough that you will need to have someone working with you until you find the thing that you need to help with your specific problem. Unfortunately, once a person develops a cough from almost any reason, the cough receptors in the upper airway can become sensitized and can then lead to more coughing with almost any provocation. For that reason, it can take some time before a cough will resolve. In kids, reactive airway disease can be something that contributes to cough, and inhalers can be helpful during acute episodes such as what you are describing. Sometimes, it takes extra help to overcome the current problem, and sometimes more than one inhaler can be needed, or even medications that are taken by mouth. Obviously, the decision about when to get more aggressive with therapy needs to be made in consultation with your doctor, and that is why you need to let your doctor know about your concerns and how your son is doing on the new medication. Please speak with your doctor.