First off, he's fine. He asked me if it was ok to eat something a friend brought over. I stupidly said yes without checking enough. I've never ever done that since he was diagnosed. I still don't know why I did it.
Soon after he had a few bites, luckily the conversation turned to what was in it. Then I knew. The dressing had egg as an ingredient. I told him to stop eating it (he hadn't eaten a lot). He seemed fine for a while, and then his stomach started hurting -- he calls it the egg stomach ache that he gets at challenges. The last challenge ended in the epi for him. I decided there was no reason to wait for more symptoms, so gave him the epi with just the one. I'm glad I did. He never developed any other symptoms, but the stomach ache lingered for quite a while. I imagine without the epi it would have definitely gotten worse.
The only good I can take from this is that this is the first time I've done something stupid like this in his 12 years of living with allergies. I won't again. We were both calm about the epi, I think given the experience in the allergist's office. That's a good lesson for him. This is the first time I've given the epi to him, first time he got it in the leg. My friend felt horrible, I kept trying to tell her it was totally my fault. He didn't have any other reaction, which is good.
It was such a fun night after a long, stressful week, and then it turned into such a stressful night. He was so good about it with me...don't worry mom, everyone makes mistakes he said. Still feel terrible, but at least he's alright.