Foot problems

The bottom of my left foot is swollen. After running just one mile tonight, I stopped because my left foot was feeling strange. The feeling was as if a clod of grass or mud had gotten stuck on the bottom of my foot, but there was nothing there causing it. When I stopped a little longer and looked at both my feet, I could see how different my left was from my right. When I pressed against the ball of my right foot, I could feel the fatty pad, muscle underneath, etc. On my left foot I could feel basically no structure at all. The texture of the skin was different, and it was difficult to curl my toes on my left foot.

I'm not sure what all this means. I would go to a doctor, but I'm not ready for that yet because I suspect they'll have nothing useful to say. For the time being, I'm going to wait it out a little longer and see if this persists. I don't know whether the foot swelled in response to some other damage, or whether the swelling itself is the problem.