My started in the exact same spot! It was my right hand under pinkie. it would pull and release on and off. Not really twitching, just pulling in and releasing. It started at easter time. it lasted in that area for about 2-3 weeks. THen it stop.
It then spread to little twitches all over my body and has now settled in my ankle's and thighs. I still get random ones in my shoulders and back. but the twitching I have now is not what was on my hand. (the pull and release.)
I am still trying to figure out what my diagnosed is, so good luck! I told my doctor/ showed my doctor and he told me to go to a neuro. So you should start there, IF it continues or spreads.
I wish you well.