Maybe your feet swelled more than normal since it was really hot. I've had a similar feeling to what you describe on the bottom of my feet and most recently on the side. It seems to happen only when it's really hot and I'm riding for several hours - usually climbing in the heat.

The first time it lasted for days.

Are your toes turning a weird color? When you push down on them with your hand does the color return normally?

Congrats on your awesome finish too!

V.