I had a similar question with an epi-pen that had been in sub-par conditions and my doctor told me not to tamper with it, to carry it with me, it probably still worked, but the best option was to refill the prescription because JIC can mean saving my life.

I've had anaphalactic shock three times, from three different things. If necessary, I'd dumpster dive for aluminum cans in order to get enough money to make sure I had working epi-pens. If you have any doubts at all -- any -- make sure you have a good epi.

I'm so sorry you had such a bad reaction. It's scary and far worse than what most people think of as an allergic reaction. I also carry Benedryl with me all the time, too.