In reply to aaronna:
If it's OA, then as you will be aware there is no cure. Usual disclaimer, seek appropriate independent advice first, but for me with it in most DIP and PIP joints, the following in no particular order is useful, but may well be different for you:
Keeping climbing - adjust grades/routes to a level that is sustainable for the time your climbing on a particular day. Then rest day or days avoiding climbing two days in a row. I've found improvements overall in managing it by keeping going with rest time, but having no set routes/grades to achieve. Some days are therefore good and some not so and even on occasions down at a level I climbed at 10 years ago! Keeping strength and flexibility in the joints is very important, and I am sure the use it or lose it applies to OA affected joints.
Little or no alcohol, and caffeine - afraid I can't give up caffeine though I should do that also.
Diet - avoid or minimise anything that cause inflammation. This will vary from person to person.
Warm up exercises essential before climbing, warm down exercises after, and hand and finger stretches/massages during and after. Don't just stop without, particularly after a painful climb.
Whilst keeping fingers and hands warm generally and whilst climbing, cold immersion of hands and fingers after a hard session when really bad. 15 - 20 mins is target. The idea is to get them really cold and to the stage that the body forcefully pumps blood into the cold hands and fingers. Otherwise generally keep the blood flowing as much as possible so promote healing.
No crimps ever and minimise use of small grips. Spread load over ideally three fingers, find ways of using holds differently - I can't use my pinkies now at all.
Avoid holding fingers bent for long period of time even when not under much load. Keeping them moving and straightening them out when you can helps even between moves. I often do some one hand star burst hand "stretches" whilst on routes when they get too painful. Being static for too long reduces blood supply.
Use three fingers for pulling, never just one, and ideally not just two. Does mean many routes can't be done if they involve finger pockets or small holds though.
Avoid torquing finger joints, and certainly minimise any rotation of joints particularly when loaded even lightly - better to remove fingers and replace.
Avoid dyno type moves/slaps and generally avoid snatching any holds. Slow deliberate placement of grip is best.
Finger taping with a good quality non stretch tape. I now always tape fairly tightly two or three of my fingers on each hand before a session and replace during as necessary; individually taping avoiding joint as you need to allow some bending, not buddy taping (the latter makes mine worse). Helps mine partly because it is a constant reminder that there is OA in the joints so find other ways of using the holds, but more importantly it stops more extreme bending and twisting of joints and keeps pressure on the pulleys which with me get affected due to swelling and bone growth.
When a joint locks, sort it before continuing and further tape if necessary. Further stressing of a joint when out of alignment is a no no in my book.
Double strength ibuprofen gel massaged in when necessary.
Hand massage with hand creams to improve circulation, warmth, encourage healing and keep mobility and flexibility as much as possible.
Oh and did I mention rest days!
Sure at least some of the above is not appropriate for some, but seem to work for me. Still going at the same average spread of grades after some 8yrs of finger OA.