What Is The Treatment For A Blackish Bruise On The Arm?

i banged my hand hard a few mnths ago now and sort of bent the hand backwards, and straight away a big bubble of blood appeared in my wrist which i grabbed n held tight,the bubble went down after a short while followed by a bruise which lasted a cpl of wks, but after that i have suffered with pins and needles in my hands and feel my wrist has now become a weak point. And also a cpl wks after the wrist injury i onlt tapped my inner elbow on the corner of the table and my arm went blackish with a big bruise, could i have damaged a vien or something ?