Pretty Face (2002)

Blurb:
Rando Masashi, a self-centered, brash karate star, was the victim of a horrific bus accident that left him comatose, his face terribly disfigured by extensive burns. Genius plastic surgeon Dr. Manabe saved Rando’s life and went to work on his face, gradually reconstructing it based on a photograph found in the wreckage of the bus. When Rando wakes up from his coma, a year has passed, and Dr. Manabe has made remarkable progress. But in a cruel twist of fate, the photo that the doctor used as his reference was not a picture of Rando, but of Rina Kurimi, the girl whom Rando has a crush on!

When Rando leaves the hospital, the first person he runs into is Rina, who mistakes Rando for her long-lost twin sister, Yuna. Rina insists that Rando come back home with her, so Rando poses as Yuna and joins the Kurimi family. Though Rando is furious with Dr. Manabe, the doctor is the only person who has the skills to repair Rando’s face--and the only one who knows Rando’s secret. But Manabe seems strangely fixated on transforming Rando into the perfect girl (in every way) to prove the superiority of his techniques! Will Rando ever get his old face back? And what will happen when the real Yuna returns home?!

Source: www.anisearch.com/manga/3787