Severed median nerve leads to calloused spots on parts of thumb with no feeling

I cut my thumb last week and severed a branch of my median nerve to my thumb. I have a small spot on pad of my thumb where I still have feeling. But the tip, the side, and the bottom part have all lost feeling.

The parts that have lost feeling have started to dry out and callous, where the part with feeling is normal skin.

All sections of the skin have been exposed to the same level of air and bandage exposure, so it's some sort of nerve(or lack there of) response.

Basically any part of my thumb that's darker, I can't feel. And it's remarkably reliable when I test my theory by prodding the different parts of the skin.

I'm getting surgery next week to repair the nerve damage.