Bluelight can't give much medical advice besides harm reduction. Gotta see a doc / PT.
I get the 4th and 5th finger numbness from time to time, but from likely something in my neck (C8 radiculopathy) and thoracic outlet. I never ended up getting a follow-up EMG.
Positional could be a more localized lesion at the ulnar nerve (cubital tunnel at elbow). With a bent elbow the medial epicondyle can press on the ulnar nerve [this isn't the only etiology, just an example...also not a full explanation] . They have braces for that which can work somewhat, but it ddepends what you have. Sometimes people can fall asleep in weird positions and get damage, or just happen to be built that way. I can't sleep some ways without waking up with both hands asleep at 4th and 5th fingers.
Best of luck! This has been my personal experience but any issues you should see someone.