I have injured fingers carrying heavy groceries in those plastic type baggies, up the stairs. I think sometimes we strain something and at the time don't realize it and later in the day, we can be surprised with a pinched nerve or joint pain. I'd try putting some ice on it. Cold typically helps with an acute inflammation.
Other possibilities include gout, or rheumatoid arthritis. RA typically attacks the proximal joint of the finger as you describe as "palmar". RA typically has swelling. Do you have swelling?

Keep an eye on it, as you may be getting a trigger finger. This is a tendon issue, and less of a nerve one.

Here is a definition of neurapraxia:
http://en.wikipedia.org/wiki/Neurapraxia

Pain in the hands can really seem huge. I ripped a nail bed on my thumb last year and BOY DID IT HURT! (I was tugging on a stuck cupboard door) I used a strong magnet on it (which I have a stash of) and it blocked the pain instantly. I put one of my neodymium at the base of the thumb at the wrist. Two days, and I was able to go without it.

I do think people with PN tend to hurt MORE when injured. Seems we get sensitized to pain somehow.