Hi
Carpal tunnel Syndrome (CTS) can sometimes be tricky. It is a compression of the median nerve at the carpal tunnel at the wrist. That compressive band is always there. Hence non-surgical methods, like anti-inflammatory medication, injections and splinting can all be done first. Symptoms may improve, but they may recur.
As the causative problem is still present. Thus, it is hard to answer your question of how long does it take to get better. It also depends on whether there are other causes. Pregnancy is a risk factor for CTS, and the symptoms resolve after delivery. If the CTS happens on the dominant hand, then sometimes may take longer than usual cause you will use your hand more often as well.
Hope this helps,
Dr Sean Ng