the extremities do sometimes suffer when other problems cause reactions. Like Amos suggests.......

I had a nerve problem in the 3rd cervical vertebrae....caused much pain in left arm and numbness down the arm...got treated, and once neck was better and arm quit hurting, my index finger was left with lingering partial numbness at the tip. It does sound like 'some' sort of circulation or nerve problem.

I'd get it looked at.