Some time ago, I banged the back of my left hand on a door frame (I think it was when maneuvering a laundry basket. Shortly after that, I had a lump on the back of my hand. It went away.
But it came back, and when the tendon of my left index finger slides over it, it kind of clicks/snaps and after a while, it hurts. No bruising or anything like that, so I have been taking ibuprofen as an anti-inflammatory for the past two days, and the swelling is going down, and as a bonus, not hurting so much anymore. I think there’s a good chance it’s injury caused arthritis. Will have to see Dr H to confirm, but I’m pretty sure.