My orthopedic surgeon told me it all depended on how bad the CTS was, how long you had it, your age, your health. There is no gurantee that surgery will be a success.
That said, I would think if hands are worse and never better, the surgeon may have damaged something in the process. It should not make it worse.
My surgeon said he found the median nerve to be flat in wrist and they slit the sheath covering to release it. The nerve may fluff up again or may remain flat and get flatter.
My wrists were ok after surgery for a year and then I painted the garage, shelves, floor, and made curtains to cover shelves. That was too much for my hands and they started hurting again and numbness in a couple fingers. They still bother me and it has been 7 months since the painting/sewing.