I was reading Novel about an AI (robot) becoming more human than the owner and the mention of probes that subdivided made me remember a paperback I read, I think on the early 2000s, maybe as a paperback. The protagonist, who was a human Captain on a starship, I think a male, was talking to an opponent over a communications screen. Said opponent used to be human, but was either infected or installed with nanotechnology which, among other things, caused his fingers to bifurcate, and then split again and again down to atomic levels. During the call, said opponent started peeling the skin of his own face, I think unconsciously.
The only other thing is that I have a very Star Trek vibe in my head about the book. It might have even been one of the paperbacks.