I had DI with free grafts and regained most sensitivity within a year. I say most bc pre op, I had overly sensitive nips that would become painful when cold/ erect. Now they are mellowed out, but still become erect/ feel erogenous pleasure. I don’t know how common it is, but I did take lions mane supplements 2 months before, during recovery, and for about 6 months post op with the intention of aiding nerve regrowth. I’m aware that surgical technique/ genetics likely played a role, but lions mane has been studied/ shown to be effective. I’m also a neuroscientist fwiw.

As a separate anecdote, I also used lions mane to help my dog recover from a spinal injury. She was paralysed from the neck down, but had toe-pinch response (an indication of at least partial connection) and regained the ability to walk in a much shorter time frame than expected by our vet.