If you're anything like me, your first reaction was "Oh, good, it's "just" carpal tunnel and not diabetic nerve damage!" Sounds strange, but that really was my first reaction, one of relief! As far as being caused by my T1D, the doctors never really said that. They said that it is a bit more common in Type 1 diabetics, but that's about it. Carpal tunnel is definitely not an "official" complication of Type 1 diabetes - at least, it hasn't been added to the lengthy list yet!
Are you right-handed, like me? My condition was also worse in the right arm, but it seems to make more sense because being right-handed, I would be using it a lot more.
The operations, done about 6 months apart, weren't a huge deal. Of course, I did get pretty nervous, but the operation is done while you're awake; they give you alocal anesthetic. You feel some pressure in the wrist as the surgeon is working, but it's over so quickly that you barely have time to react! From the time I walked into the operating room to the time I walked back out, it was only about 15 minutes!
As far as pain right after the operation, I think it all depends on the person. For my first one, I was fine right after but later that night and right through the next day, it was very painful! For the second one, I was fine. In fact, I went to a wedding the next day! LOL
Now that I am all healed up, I am so thankful to have had the operations. No more pain, no more tingling, no more numbness! It's wonderful!!! Be aware that the operation is not successful sometimes, according to my surgeon, but that's only on a very small percentage of patients, something like 3 to 5%.
I hope this helps! All the best!