The novel “Star Surgeon” by James White was published for the first time in 1963. It’s a fix-up of two stories published in the previous years. It’s the second book in the Sector General series and follows “Hospital Station”.
Dr. Conway must try to treat a patient with very little information about its species, who’s suffering from what appears to be a skin disease. Concerns arise because it appears resistant to any treatment and is unconscious, so it’s impossible to ask it any questions. Tests conducted by the people who found it suggest it was traveling with another member of its species but devoured it.
Dr. Conway finds a solution to the medical problem by going against what appears to be confusing and even contradictory information, obtained in part from other beings who know his patient’s species. What seems like a happy conclusion turns out to be just the beginning of a mission quite different from what Conway is used to, one that brings him into the midst of a situation that could lead to an interstellar war with an empire willing to attack the Hospital Station.