Hi, those sugars are they fasting ones or tested one to two hours after a meal ?
Also are you on Metformin ? as it can deplete B12 levels which are crucial for nerve health.
As far as exercise goes, you could try walking in a swimming pool as it is non weight bearing, just walk up and down the lanes of the pool when it is very quite, I used to go very early in the morning [ hardly anyone there ].

R- lipoic acid at 100 mg per day should help with the burning feeling, may take a few weeks though to see any improvements.
Be very carefull of any low sugars as this can damage the same as high sugar levels.
all the best
Brian