It could also be irritated nerves.

The auto accident I was in (2 times ago ) I took the steering wheel in my chest and was bruised in-between the thumb and index fingers from bracing myself against the steeering wheel. For about a week, both my index fingers were J U M P I N G uncontrollably. It subsided and the index fingers have been relatively quiet ever since.

I hope what you have is irritation and not dammage regann!