Is credit by exam a bad idea?

Let me give you some context. I took Physics 23 during Spring and I ended with a D+, when I needed a C- to fulfill the prerequisite for physics 24. I believe that I have a strong grasp on the material, as I went to office hours twice every week for about half the quarter (after I bombed the midterm), and I think my low grade was due to my lackluster performance on the first few homework assignments and the midterm (I also have personal reservations about some of the assignments post-midterm and the final, but I don’t want to blame the professor for me failing the class).

So with all that in mind, is credit by exam a bad idea for fixing my grade? If I end up having to retake the class, I’d have to do so this summer, and I really don’t like the idea of having to dedicate another month and a half to a class I already put so much time into.

Is there any other option besides retaking the class? I know I could talk to the professor or department and try to convince them to up my grade but I’m honestly not sure what valid arguments I would have for that.