Suggest Treatment For Stiffness And Pain In The Thumb

Back in July I injured my hand when pushing a wrench. this injury was between my thumb and the palm and is still sore and I can not bend the last joint ( think call ip joint) of my thumb backwards as I did before . I can slowly bend it when pushing with the other hand . then it starts to hurt in joint and between thumb and palm. was hoping it will heal on its own. pain will go away the next day but joint is still stiff.and won't bend backwards like before.