Last night, my dear husband educated me about the anatomy of a spider bite. He pointed out the two bumps in the center created by the pincers and where the venom was injected. Then he pointed out the two blisters as it moved outward.
Then he pointed out the swelling created by the venom. Ah, that explains the stiffness that I had just assumed was a one of my typical over-extentions.
Hmmm, I would have preferred if I didn't learn this fascinating lesson on the outside of my left ankle. On the other hand, I will remember it well and it hasn't stopped me enjoying my lovely forest!
Day four and no worsening, I'm sure my body will fix itself eventually. So cool that we self-heal so well.
Update
Andrew found out what kind of spider it was... "grass spider". It matches the pincher marks and all the data we have and he found one on his wall.