Suggest Remedy For Immobility In The Joint

a month ago I fractured the tip of my pinky, right about the first joint....The finger was hit by a baseball and pinched betwwen the knob of the bat and the ball. This caused basically a cut/small hole put in the side of my finger....went to the ER, antibiotics and splint it. Now the cut has healed and finger is healing...but, I have very limited mobility in the first joint....what are some excercises i can do to help with this?