In reply to TomAlford:
Hi Tom
I have pretty much what you describe in my left middle finger PIP. Mine has never got as bad as yours but doing the following has helped me manage it.
1) crimp less. Especially full crimping. Get strong open handed and dragging as this helps a lot. I do circuits inside banning use of the thumb to train this!
2) ice immediately after an indoor session if it's causing you grief the next day. It works.
3) acupressure rings are useful to keep blood flow to the area.
4) forearm massage. I have no idea why this helps and it may be a placebo but it seems to work. I get them particularly near the elbows on both sides of the forearm. Even if not directly connected this will help other things!
5) taping it. X tape or both sides of the joint. Again probably a placebo but tends to remind me the finger is a bit tweaky when I look at it and I then climb accordingly.
There's a good UKB thread which I started which discusses in a lot more detail. Mine definitely hasn't "healed" but it doesn't really affect my climbing currently, which I'll definitely settle for!