Bruised knuckle? help please :)?

ok, so i punch walls to get out my anger all the time, and my right middle knuckle is bruised, but i don't know the extent of the damage done. i've been doing this several times every few days since around november/december (please don't judge). when i hit something it swells up immediately and goes purple, with the surrounding area going a bit green. it looks a bit darker and more rounded than my other knuckles, and it feels really weird. like.. if i stretch out both of my hands, the tendons on my left hand are nice and smooth, but on my right hand the middle one is a bit lumpy and it hurts if i put pressure on it. i don't think it's broken because i can move it fine at the moment, although just after i hit something, i can feel a sort of grinding when i clench my fist, and it might become a bit stiff. also, when it swells up it feels really.. squishy? probably blood under the skin but i don't know.. how bad is the damage since i've done this for a long time? thanks x