Can you type with your left hand? You might like to try gently alternating keys. Start with all four fingers in a row touching on adjacent keys ASDF, then press your index finger (F), press down, release then your little finger (A) and if you can do that, your middle finger then your little finger which will probably be much harder. I'd be surprised if you can alternate your ring and pinky on the keyboard but if you can it would be a great exercise.
If I were you I'd then be playing with very light pressure exercises over the strings - not touching them down to the fretboard, but hovering about 1cm above the 3rd string in a line in say 7th position, then VERY slowly touching each finger down to the string and returning it, and trying different sequences depending upon how hard this is (again, ring -pinky will be the hardest)
At some point in all this you will discover the threshold at which your pinky involuntarily flexes, and indeed when your ring extends involuntarily. Once you can really sense this you are on the starting block to recovery, so to speak. Any attempt to try and force control over your pinky or ring finger will be a waste of time and may make things worse.
HTH
BTW, just curious - are you a rock player and did you play lots of left hand legato shapes with a wide spread (if you listen to players like Satriani or Holdsworth you will know what I mean).
