Suggest Treatment For Allergy In An Autistic Child

Hi, my 2.5 yr old son has many allergies that break him out especially around his mouth. His known allergies so far are milk, whey, casein, dust, dogs, cats. We took every measure possible to ensure he stayed away from all of these. He hasn t had any contact with any of these things in about 4 months. He also has eczema that has been flaring up. He has started to break out on his eyelids the past 2 months and we have no idea what s going on. We can t get into his allergist again for more testing until August 13th. He takes benadryl and zyrtec every day and we use multiple eczema lotions, nothing is helping. I m so frustrated! What could be causing his eyelids to flake and swell like this?? They get so swollen that they pretty much swell shut! He is also severely autistic and completely non verbal so I can t understand what hurts or how it feels