Saw this post and I have about he same exact problem except I did get stiches: Hard lump on knuckle after using handgun, sore to touch. What could be wrong? A few months back I was at the shooting range. My handgun recoiled and smashed against my left thumb knuckle. It cut it very deep (I probably should`ve got stitches but I didn`t). The cut actually healed just fine,but I now have a small hard lump on the knuckle (at the exact point of impact where the gun smashed against my knuckle) that feels like it`s part of the bone. It`s still sore if I press on it,and my joint is sore when I use force with that thumb,such as making a fist or pressing down on something using that thumb. What could be wrong?