A lot of times, pain in the wrist is not carpal tunnel or stuff like that even though doctors will often chalk it up to that. It is:
a) referred pain from the neck or anywhere else along the path of the nerve from bad posture. The nerves start from the back of the neck, run down the neck's side, under the armpit and through the arm. They can get pinched anywhere in between which will lead to numbness and tingling pain. Posture and ergonomic desk setup will help with that. Nerves do heal up albeit a little slow.
b) sharp pain from gripping too hard at a pen for prolonged periods of time, which clenches up the muscles in the arm. There is actually nothing in the wrist that can cause pain, barring the inflammation that is carpal tunnel. (Incidentally the test for CT is pretty easy: press on the wrist for a minute. If it's CT the pain will be unbearable. If it's not, it will actually be a relief to press there.) Anyway, when the arm muscles cramp up, they pull on the tendons and they in turn pull on the nerves which is why it hurts.
In both these cases however, the origin of the pain is not where it actually hurts and that is very important to know because things like wrist braces will temporarily relieve you but will not address the root of the problem and you might ask for the wrong type of physical therapy and in a month or two get back to where you started.
Either of these types of pain are warning signs to treat the body better because when it gets to the breaking point it will hurt. A lot. Breaks, self-massage, correct posture and above all incorporating appropriate exercise to strengthen the muscles that weaken when you spend all day hunched over a desk are a must. I cannot stress how important posture and strengthening exercises are. If possible, take up swimming. It will build muscle and help with cardio without straining the body.
In cases of acute pain it is actually better to consult a physiotherapist skilled in sports injuries (ie. tennis, which is pretty similar to artists' RSI) than a doctor because they tend to have better experience with muscle strains and repetitive stress injuries.
Finally, when I speak of posture, I mean posture correction everywhere. There is no point in drawing sitting up straight and then spending hours craning down at the phone screen and wrecking the spine. That way lies a herniated disk and that is the last thing you want.
source: 3 years spent getting rid of RSI pain.