Hey guys. I have the numbness in my pinky, ring fingers, and half of my middle finger. Through a lot of research (and much to the dismay of an angry rheumy who I called out on her mistake)... I found out it's caused by ulnar nerve compression.
The carpal tunnel numbness is typically (unless very severe) on the other side of your hand... thumb, pointer, and other half of middle finger...
That's how you tell the difference. Braces will help carpal tunnel but not ulnar nerve. Everything I've read on ulnar nerve compression says it isn't damaging, just annoying... so you just have to train yourself to not sleep on your hands. (I know, easier said than done if you are like me...)
Also, mine is WAY worse when I'm in a lupus flare. In fact, it might only happen when I'm flaring. I attribute that to the fact that everything is so swollen anyway, the nerve is easier to be impacted and compressed.
Hope that helps... I'm not trying to diagnose, just passing along what I learned about me and maybe it can help someone else. Be well.