Yikes, what a mess!

One of the most frustrating things about Owen's allergies is not knowing what is going on. That is exactly what happened today. When I picked Owen up from day care, his skin looked clean. I didn't do an inspection, but I was not concerned. Although there was a "soreness" to his skin, but it was mild. I brought Owen to the mall to play at the playground, since it is a hot day. Owen played at the playground for 30 minutes. Then he started coughing a dry cough. He kept coughing, so I went to check on him. And I heard him wheezing, which is a first. I thought to myself this can't be. I listened to him for a minute, and the wheezing continued. I took Owen off the playground and bought him some juice. (I always give him a drink when he shows signs of a reaction. It gives me a chance to evaluate him without his hands getting in the way. It also serves as a "time out" to evaluate the situation). Owen was not interested in the juice. I gave him benadryl. He continued to cough, and his nose started running slightly. His face was red and slightly puffy. I started getting very concerned. I decided to get the epipen handy(which I thought was in my car, but it was in my purse the whole time). On my way to the car, I thought I should notify mall security, so they can be prepared to help me if I needed it. Security called 911, and an ambulence met me at my car. By the time the ambulence arrived, his coughing and wheezing stopped. His face was still red and puffy. The paramedic evaluated him, and said that he didn't hear any wheezing, and said it was my choice if I wanted Owen to go to the hospital. Since there was no respiratory issues, I just went home.
Owen's face continued to be slightly puffy. He has horrible eczema on his legs, chest, arms, and underarms. When I brought him upstairs to put cream on him, it seems like his face got worse as I was applying cream.
When he ate dinner, he sounded congested again, but did not cough or wheeze. I gave him Nasonex. He already had Claritin earlier that day. I gave him benadryl again before I put him to sleep.
It is so hard to judge what to do. I felt like I over reacted when I got mall security involved, but if I was helping another mother, I would have done the same thing.
What happened today??? What is happening with my little guy?