1) No matter how careful you try to be, when you live in the country and work on your property, you will inevitably stir up a hornet's nest. Therefore, know where your nearest ER is located.
2) Contrary to what you may logically, reasonably, think about immune response building up resistance through continued hornet bites, the exact opposite happens. With every attack the body's response becomes more crazy. In other words, it gets worse. Last year I stirred up an underground nest and sustained 25-30 bites all over my arms and chest. While I felt I was on fire and only took a first dose of Benedryl a good twenty minutes later, the body reaction was nothing compared to the four or five bites this time where I soon found my right hand looking and feeling like a catcher's mit and my left ear, easily twice the size of the right, hanging on my head like a weird, heavy, B-sci-fi movie prosthesis. Wild also was the sensation of hot jelly being injected and flowing under the skin as the reaction progressed and the swelling spread. It's also a good thing if your throat doesn't close up within the first hour or at least before you get to the ER.
3) You can get a pretty good idea where your lymphatic system is located in your body by the way they welt up through your skin in a fiery way as the reaction progresses.
4) Benedryl taken within the first 5 minutes (this time we had it in the house) is a very smart thing to do. However, the stomach is the second greatest producer of histamine and pepcid is also beneficial to have around as it suppresses stomach activity.
5) Exofficio insect repellent shirts, while pretty damn expensive, are worth their weight in gold. They're like Kryptonite to mosquitos and horse flies but I was stunned by how well they worked against the hornets. They just couldn't hang on. It probably was the single reason I didn't suffer more bites.