Ive had carpal tunnel surgery. i havent handwritten much in the past several years, just text and type. today i was writing on a rare occasion and it was messier than it used to be. some words harder to write. lack of use, surgery, ms? aging?

Use it or lose it. Fine motor movements like the smoothness of handwriting are a skillset that you maintain by regular use. Surgery on the hand can disrupt some of these skills as can the nerve compression that leads to the surgery. I would not assume you had a dread disease based on the cited information. Practice can overcome decline in skill unless there is long term damage to the nerves.

Carpal tunnel surgery is often only partially successful, and residual symptoms may persist. As mentioned, practice will result in more successful writing. This is, in no way, a presentation of MS, and at age 47, not a consequence of aging.