Not very easy to understand from here, it seems like there is a nerve involvement as you are complaining of an objectifiable loss in sensation and muscle power too, although I can't really know whether the weakness you feel is due to pain and so you refrain the movement or it is indeed a neurological problem.

And what about the other fingers? are they affected too? either dorsally and on the palmar surface or both? (sorry it's not to being picky but different nerves innervate different part of our fingers)

Can you do the thumb up? can you bend your thumb over to touch your little finger?

Let us know what the neurologist thinks about it!

All the best