Numb Thumb

So... today at work, I discovered that there is an area on my right thumb that is numb. I believe that this happened recently, but as of yet have not diagnosed a cause.
The numb spot is about the size of a dime and it is right on the pad of the thumb, almost centered on the whorl of my finger print...

here's a photo for clarification...



No, the skin is not actually discolored. I colored it with a highlighter to see how big it actually was because I couldn't feel it... and then I outlined it with a pen... to make it visible for photos... yes that's what I do when I'm not doing homework in the last week of class... I color my numb thumb and take photos of it...






By the way, do you know how awkard it is to take a photo of your dominant thumb with your non-dominant hand... very.


So, anyway, it's not really problematic right now, just kinda annoying. Oh, and for more info, only the center is completely numb. Around the edges of the spot it's that tingly feeling like when you've had novacaine at the dentist and your lips are all puffy and tingly feeling... not the pins and needles of a sleeping foot... but just tinglely. Yes, I said tinglely...

So... if anyone has suggestions, causes, remedies for restoring feeling to my Numb Thumb, I'm very interested in hearing them...
Oh, and let me know if you think it's serious...
I doubt it, but you never know.