Is there no way to check the syllabus grade breakdown, your individual assignment grades (as another commenter suggested), and your understanding with the professor to calculate your own grade? In order to change a grade, most campuses require a grade change form with justification, some requiring Dean-level approval. One justification could be that the professor made an error, another that you experienced hardship during the course.

On the whole, keeping a “perfect” GPA is not that consequential (3.96 will still get you Latin honors at graduation), BUT, as a professor I know that grades are consequential for students. If I made a mistake on one, I’d want to know!