A couple of years ago, I made the mistake of playing in 2 events in a very large tournament and strained my wrist. I ended up taping it up, but it never really healed until I stopped playing a couple of weeks and focused on icing and stretching it. I don't know if it works or not, but this guy told me about 'active' stretching of the wrist and it did seem to help. It might have been a placebo effect, but it tricked me!
I'd take time off, like chas said, it is gets worse you could be looking at something chronic or even surgery.
'Tennis players have fewer faults'