Emily, I have been following your posts and you have a lot of the same symptoms that I do. I can only encourage you to follow up with a neurologist and get a skin biopsy but given your family it sure sounds like hereditary neuropathy.
There are two main types, the first and most common affects the myelin sheath first, the second affects the axons. I have type 2, with severe SFN and muscle wasting. I get exactly the same sensations holding the iPad so I rest it in my lap.

Is the numbness more prominent along the last two fingers and up the arms? That is usually the first to go. Have you had an EMG/NCS?