Pushing things a bit too fast on a sketchy surface results in:
The problem was that I couldn’t really tell what’d happened given the colours!
It hadn’t had time to swell by that point – that came later that evening. 😯
Three days later, and lots of cleaning out / and some of the swelling going down a bit and I could see what I’d got:
DIY fixed, so I’ve got no idea what happened inside, but I had a *really* sore elbow for about 6 months solid afterwards, so much so, if I bumped it against anything, or forgot and leant on it I’d go all kinda shaky/sweaty from the increase in pain.