I have a lot of experience in this area.
First, go to an Allergist. Dr. Bernard Silverman in Flatbush is EXCELLENT and will be able to help you in no time. He takes insurance.
Second, since I personally am allergic to just about everything airborne (I was tested for 20 common airborne allergies… allergic to 19/20), sometimes I just take Benadryl to knock out the allergies when they’re really bad, it doesn’t make me too drowsy. It works for about 12 hours, so it’s not a long term solution, but it will knock out the current reaction. However, if you take Benadryl too often, it stops working as well. So you can use this as a temporary measure until you can get to an allergist.
Thirdly, in my experience, allergies that are untreated get worse and worse until the winter. So don’t ignore it – get treatment now, so your son can live a normal life. It is not worth the wait, if he has allergy – induced asthma it can also get dangerous. If his throat is hurting or he has a cough or wheeze – get him to the doctor quicker. He may need steroid inhalers.
Refuah Shleima! I hope he feels better soon!