Can hair ungrey?
 

So a few of my hairs lost their dark hues, as is normal with age. But then plucked out the hair and took a closer look. The root wasn't grey. Now my hair is pretty long but after a several inches of grey at the tip its suddenly back to normal color.

Leaving me wondering what the heck the deal is

I've never heard that occurring to be honest...

If I was to take a completely unsubstaniated and random guess, I'd reason that since outside factors such as stress can be a contributor to graying hair, that you happened on a situation where you started greying for a period due to this "X-factor" being on the rise. Then it started ungreying once the X-factor went down to normal levels.

Obviously, you bits that went grey cannot regain their normal hue, but the more recent bits that are growing away from your scalp are gaining the more youthful hue.

The level of surveillance needed to verify something like that is itself disturbing
 

Don't lie to us, we know you've been stealing virgin's blood from the blood bank and bathing in it to maintain your own unnatural existence.

Yeah, I've had like, one or two gray or white hairs on my arms or my head, they are just random sometimes. I'm not gray or white in the slightest. Just for whatever reason this or that hair grew in white.

I mean if you are heading for actually going gray I think you can tell.

His story was funny and touching, but just a little awkward at the same time.
 

Well, it might not be directly related to your case, but it seems that a lack of blood-flow can cause hair to gray, and an increased blood-flow can let the hair get back its vigor... at least if my anecdotal evidence of anecdotal evidence is any proof.

When I was at college, a guest-speaker, apparently a member of the church (I didn't know many non-college students there), had come to thank everyone that had donated for his heart-transplant surgery (it had happened during off-months when I was at home, so I didn't actually know the guy). It had been successful, and he mentioned (by way of an ever-so-slightly risque story 'bout he and his wife) that his head and chest hair - once gray - was now coming back in as black; it seems that it had grayed from lack of consistent blood supply because his old heart hadn't pumped blood very well.

(He also mentioned that his skin - especially the tips of his body, like his head - had started itching a lot after the surgery, his nurse telling him that it indicated increased blood-flow, not terribly different from the sensation you get when your arm falls asleep, but then the blood begins flowing again.)

If you had undergone a period of high stress/blood pressure, but that lowered, that may - may, mind, as I'm absolutely the opposite of an expert - have something to do with it.

They also promise to solve a few other things completely unrelated to your hair as well! >_>