My advice is dont overdo it in the early days but dont do nothing... I've have had multiple broken wrists and a major motorcross accident that exploded the joint surface on my ralius. The wrist is full of metal, and at the time, I thought riding was over. I did physio, did the exercises, started out small and have about 80% movement and strength with it these days.
Now I regularly race downhill, enduro MTB and have started trials in recent years with my 10 year old son.. Sometimes the smallest mistakes hurt my wrist, hopping on the front wheel and land off balance etc.. you learn the limitations and as TomWood said, you adjust the bike if it helps.. Stay motivated, the human body has amazing way to get better with time if you do the right things.. cheers!