I've read the book you're talking about and now I'm curious too.
This one is more likely the answer, though I don't recall reading this author before.
"FROM A CHANGELING STAR" by Jeffrey A Carver
Across the galaxy, tensions are rising between the authoritarian
Tandesko Triune and the free-marketeers of the Auricle Alliance.
Nevertheless, scientists of both sides have come together in Project
Starmuse, to observe the giant star Betelgeuse as it goes supernova.
At the space station imbedded inside the roiling star, the team
anxiously awaits the return of the one man essential to the success of
the project. On Kantano's World, astronomer Willard Ruskin must
discover why someone has infected him with nano-agents - artificially
intelligent, microscopic computers, which alter his appearance, his
memory, his very DNA. Drawn into a conflict from which not even death
will free him, Ruskin must find a way to reach Betelgeuse before his
enemies sabotage Starmuse...and humankind's future among the stars. A
harrowing journey from inside the human cell - to the mind of a dying