My Eleven Year Old Son Ate Some Chocolate Fudge Cookies

My eleven year old son ate some chocolate fudge cookies and may have had an allergic reaction, he complained of itching, headache, chest pain, upset stomach and nausea, I gave him benadryl and the itching stopped but in the morning he stayed home from school, he felt bad and had nausea, I gave him a generic allergy pill and when I came home he still had a headache, was feeling hot but did not feel like he had a fever, upset stomach and nausea. I gave him tylenol then later I gave him another benadryl then he complained his sides were hurting. He is resting now what do you think of this?