Short term I used a splint and tried to cut down on the time I as using a keyboard or mouse. Outside work, no gaming and minimal computer time. I kept this up until the pain subsided.

In parallel, I switched to a trackball instead of a mouse. Other people I know went with a vertical mouse. I got a giant mouse pad for my desk with wrist supports for both my keyboard and trackball. This is also a good time to double check your whole setup chair, desk, monitors making sure you have good posture