Suggest Treatment For Pain And Stiffness In Thumb Joint After An Injury

i was in a 4 wheeler acciddent over 4 months ago after i wrecked i hit my thumb that swelled alsmost immediatly. It currently feels really stiff and also if hit on the tim of my thumb i get horrible pain.The base of my thimb swelled and was purple and also first joint below thumb nail is very stiff.