I can relate. Some unknown stinger nailed me on the front of my neck while descending a fast hill on the 4th of July. MAN! I don't remember how the sting site becomes so itchy in the several days after.
I also got nailed by some stinging insect on the 4th of July. The bugger got lodged under my helmet strap and stung the s**t out of me until I was able to pull over and rip my helmet off. Then, I compounded the problem by finishing my ride instead of heading home right away and putting ice on the bite site. I ended up develping a golf ball-sized welt to the right and slightly below my right eye. Eventually the swelling spread laterally under my eye so that I looked like a prize fighter who lost a tough 13-rounder. Fortunately, it did not really hurt--the stretched skin from the swelling just felt weird. The swelling slowly went down over two days and I recovered with no issues.