Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Go to urgent or emergency care for rapidly developing severe pain and numbness after a wrist injury, major swelling, bleeding, or a tight cast or dressing.
Sudden symptoms involving the face, speech, balance, or an entire side of the body also require emergency assessment rather than routine carpal tunnel follow-up.
Visible shrinking of the muscles at the base of the thumb also needs prompt assessment.
These changes can indicate more advanced nerve compression.
Contact the care team promptly for increasing redness, warmth, drainage, fever, severe swelling, worsening weakness, or fingers that become pale, blue, or unusually cold.
Routine follow-up is appropriate when symptoms are stable and being managed with a splint or activity changes.
A clinician may review sleep disruption, numbness, hand function, splint fit, and whether further testing or treatment is needed.
Seek an earlier appointment if numbness becomes constant, symptoms spread, objects are being dropped more often, or the thumb becomes weak.
The article also says
After an injection or surgery, follow the treating clinician’s instructions for wound care, activity, and review.
Every sign above is quoted from the sofidex article on Carpal tunnel syndrome. If you are not sure, err upward — it is always reasonable to be checked.