The really annoying part is I'm not even sure that formication really describes what I'm feeling. It's just the first thing that popped to my mind when I first experienced it, and that might just be because of my history in drug abuse research. I've heard of heroin addicts talking about bugs crawling all over them during detox, and it's the only thing in my experience that even comes close. Those addicts seemed far more disturbed by it than I am though. It would bother them while awake and was apparently distracting enough to really complain about. As for me, it's only been a while trying to sleep thing. That means it's either something completely different or maybe I'm just suffering some early onset.
Anyway, there's nothing to do but wait until it passes. It always goes away after a bit. At least it has in the 3 or so times I've experienced it thus far.