I have some carpal tunnel evidenced by a perpetually swollen left ring finger and some hand numbness. I just bought a guitar and I have trouble positioning the ring finger on the first string on a G chord. It's because my ring finger won't bend enough. I can work around this but I'm wondering if guitar playing will exacerbate my hand conditions. Thoughts?
it is possible that using it will exacerbate the problem. I'm not a medical expert so I cannot tell you exactly about anything. My best suggestion is to go talk to a doctor about it, they can both help you with the medical problem and at the same time you can ask them if it is safe for you to be playing guitar.
That set aside, generally if using something that is injured is hurting it more it might be doing damage, and you should maybe work it a little less. So if you are doing it and it's not causing extra pain it is probably fine, but if you're at all unsure see a medical expert who can give you a professional opinion.
I would say the opposite. Heavy computer use is bad for a guitarist, I am such a guitarist. I have answered other questions about this topic, but from a different perspective. If you already have the CTS you need to see a doctor and get treatment. I wear a wrist brace when working on the computer and that has helped tremendously. You can also do physical therapy and there's surgery for correcting the issue.
In my personal experience I find that guitar playing is therapeutic and helps reduce the effects of CTS. However I play with near perfect hand posture form decades of private lessons in modern and classical guitar. If you just pick up a guitar and play Jimmy Page style (wrist bent in with thumb over the edge of the finger board) you will definitely make is worse of develop a new set of disorders. Many musicians suffer from micro trauma injuries but in my experience this is usually due to poor posture and bad technique. This is probably what led to your CTS. If you are typing with the correct hand posture in theory it shouldn't happen.
So my advice, after seeing a doctor, is take lessons and learn proper technique and posture. It pays!