Definitely take the Benadryl. I slid my hand over a wasp on the water hose once and my hand swelled up like a balloon and then it itched like crazy! I ended up going to the urgent-care and getting a Z-pack (steroids), which helped immensely.

You might consider seeing a doctor of some sort, even if you don't get any other symptoms. I personally couldn't stand the itching.

I can barely stand to roll up the water hose these days, because I'm wasp-shy.
Karen