Hand pain?

Yesterday I threw my first pen since last season, 24 pitches all fastballs nothing special. After I finished i noticed that there was a pain in my throwing hand (more around the index and middle finger than anywhere else).
I found a picture on google and circled where most of the pain was.

After about 20 minutes there was only pain when I bent my fingers back to strecth it or tried to grip something tight with my fingers.

About an hour later I went to play some piano and I had much less power, speed, and control with my right fingers than ever before. I didn’t really have a loss of grip with my hand, just my fingers, so I don’t see it being a symptom of tj (I hope). There is barely any pain today and nothing but the cold weather is stopping me from playing correctly.

Has anyone else experienced hand pain like this? I’d really like to hear any feedback on this because I’m starting to get pretty serious with piano and I plan on playing the rest of my life, I don’t want a simple hand injury to hold me back.

Oh, the bullpen went great btw. Feels good to throw finally :smiley: I was cravin for a while.