I think my leg is gonna fall off!

Well, not really. But it is doing something weird and I thought I'd write about it here in the hope that some arm chair doctor would know what's going on! I have a spot on my left shin that will suddenly feel warm for a few seconds...and then it goes away. At first I thought I'd had my legs crossed and my nerves were just readjusting to the room temperature or something like that, but it does it randomly when nothing has been touching that spot. It doesn't hurt...although now I think I can feel the spot even when it's not warm (but I think that's just a psychosomatic symptom.) So? Anybody have any idea what it might be? I thought blood clot, but it comes and goes and the skin is not unusually feverish or swollen in any way. Maybe a nerve is just freaking out on me?! Stranger things have happened, I'm sure! Alright amateur Gregory House, MDs!! Get to work! Diagnose me!!