I cut my left trigger finger knuckle deeply while opening a package with a large sharp knife. It bleed profusely for about 10 mins and stopped bleeding after wrapping it and keeping pressure on it. The cut has healed now, about a month now. But there is a very hard lump underneath my scar on my knuckle now. I can move it just fine, but it hurts if you hit anything or even graze it on something. What is this hard spot on my knuckle and how can I get rid of it?