There really should be an injury sub-forum... anyway
I've had a niggling finger injury since about February or so. Appeared relatively quickly, no popping noises, tender on the A3 pulley. Interesting was that the worst holds were probably pinches and slimpers, rather than crimps. I tried rest (I had a back injury so got 3-4 weeks of free rest...), I tried rehab exercises e.g. powerfingers. I tried taking it easy. Things didn't really improve, and I was kind of ambling along with a hurt left hand for months.
Then I decided (since nothing else was working), to try and stretch the finger a lot more with extensions (i.e. bending the finger backwards towards the back of the hand). Fairly quickly - major improvement. About 2 weeks on, I can climb as if there was never an issue. My original idea was that doing this might stretch that finger's tendons by fractions of a millimetre to take the pressure off the affected area, but what I think actually happened was that the tendon had gouged a little groove/tear into the pulley, and the extension was physically pulling the tendon out of the gouge for the rest of the day, allowing it to heal. I did hear during the injury period, a fine tearing noise - like someone peeling sellotape in another room, which I suspect was scar tissue forming very weakly in an incorrect place. Has anyone else experienced something similar, specifically revolving around extensions, and whether what I'm doing has any consequences that I'm not aware of?