I'm looking for a book in which the main character was sent to a prison type planet made of crystal. He wakes up with a symbiotic creature plugged into his ear. The creature is able to communicate through plug in. The creature manufactures new crystal parts for the main character to survive, but does it when he's sleeping; such as changing out his eyes and later internal organs. Read it in the mid 80's, but I think it was written earlier. Any help on this title would be appreciated. Thanks
Possibly Sentenced to Prism by Alan Dean Foster? Although it really isn't a prison planet, the title makes it sound like it, and all the crystal stuff fits.