I was having trouble with numbness, tingling and paralysis in my
left hand last year and it was attributed to cervical nerve damage.
the neck is delicate and the signals that control the arm and hands
come thru there. I had been going to a chiropractor but the doc that
did the MRI cautioned against neck adjustments (cracking) as there
might have been more damage done by that.

How are your finger tips? you do not mention any problems with your
callusses. there are probably some ways to help build these up too.
and ways to break them down....such as by washing dishes...

you might also try some of those gloves with the fingers cut off.
dancers often wear knee warmers...to keep their muscles warm...and
that might help your hands too. good luck...how do you find time to
play for over 2 hours every day?