It doesn't sound like Carpal Tunnel Syndrome to me, based on the above description, but Frozen Shoulder springs to mind.
It could well be a result of the injury, but the good news is that it is not a big deal, the bad news is, that it may take at least six months to settle. Anti-inflammatory drugs (e.g Ibuprofen)would be the first line of attack and then proceed from there.
I think that Frozen Shoulder (Capsulitis) is more common in Diabetics, but I may be wrong....check it.