What's your earliest memory of the worst pain imaginable?

So when I was very young I was with my nana who loved to garden and we went into the backyard and she handed me aerogard and I thought good stuff! I'll spray myself, you spray yourself with this stuff to keep the bugs off. I accidentally sprayed myself in the eyes!!! OH MY GOD!!! I'd never known such pain in my entire life!! The worst part was the realization that I couldn't escape the agonizing fire that was burning my eyes!!!