Update:

I saw my neurologist this morning, and after a thorough exam, she believes my issues to stem around vascular insufficiency rather than with a neurological root. Vascular insufficiency can lead to nerve pain, due to lack of blood flow and swelling. Which I do have on that one leg (varicose veins, a bit of Raynaud's suspicion) - so that makes sense.

Because it's so isolated, she does not think there's any cause to assume systemic disease, even with my higher than normal SED / CRP numbers, as those can be attributed to PCOS/obesity.

She's referring me to a vascular surgeon, and if that is uneventful, to an ankle orthopedist to assess for structural issues that are causing referred nerve pain from ankle area to toes.

The pain is searing - but only in the one foot. I can tap my ankle or just accidentally touch it when putting on socks, and the pain refers down to the top of my foot near my toes, and it's intense. But that's RIGHT where my swelling occurs... so I guess, while I don't have answers yet, I feel like I'm on the right path.

Thanks for bearing with me, y'all. The internet is a scary place when medical issues go unanswered!