I was thinking about this, but I'm wondering if:
a. The circulation is just bad in general (like cold ears/hands), and the heat is actually helping by increasing the blood flow?
OR
b. The circulation is normal, but the damages nerves are overcompensating by dilating the vessels too much and allowing too much blood in (and therefore swelling)?

It's funny you say that because my podiatrist said almost the opposite Well, he said, don't worry about the hairline fracture and focus on the neuropathy.

Actually, I should mention that right after that visit (4.5 months after injury) I started putting weight back on the foot, did one contrast bath and the toe came alive - burned really bad all night long - I interpreted this as a good thing though - that maybe I had them firing again - not sure if it was the weight bearing or contrast baths that did this though. It was only for one night though, it died down over the next few nights.