Can Sprain Cause Red Bumps On Fingers?

I am a 31 yr old female. about 1 to 1.5 months ago I sprained the top knuckle of my left pinky. I heard a pop when it happened. Now there is a large red bump covering the finger from the sprained knuckle up. Range of motion is slightly limited and there is mild to moderate pain. I've noticed what looks like a lunula (which I don't have on my pinkies) showing up over the last week-ish. Should I be concerned or is this all part of a heal-by-itself sprain? Your help is greatly appreciated.