A few tips from a nurse and a mom of a kid with a life-threatening allergy.
Benadryl will NOT prevent an anaphylactic reaction. It isn't strong enough. Anaphylaxis (which can kick in within seconds to minutes of ingesting the crap) will cause the child to die within minutes. The Epi-pen and inhaler ALWAYS need to be where the kid is, not with the mom. And even with the shot of epinephrine, the child will need to be taken to the hospital. Epi-pens just buy you time to get to the hospital, so the child doesn't die before you can get there.
When traveling, call 911 for emergencies (anaphylaxis totally qualifies!

) Don't bother trying to find the nearest hospital...you could get lost and then your child could die.
When leaving your child with people you don't know, always find out if there is someone there who is trained to use an Epi-pen and inhaler. Talk to them and make sure you're comfortable with their ability to use it. If there isn't such a person, don't leave your child there.
And never, EVER trust people in restaurants to tell you the truth. It is all good and well to tell them about the allergy and ask them to be careful...but DON'T COUNT ON IT!!!! They lie. They lie all the time. (But, they don't lie as much as they used to.) Always assume they might be lying and be prepared to deal with it if your child has a reaction.
Trusting others is kind and nice, but when it is your child's life you can't take the risk. Even if they aren't lying, mistakes can happen.
I'm guessing from the info you provided that, so far, your child hasn't had an anaphylactic reaction. But now that she's had the hives, it could be worse next time. Get a
good allergy/asthma specialist to help you with what might come.
So, welcome to the club and good luck with being the mom of a life-threatening allergy kid! It isn't for the naive or for wusses, either.