I think you may be worried about the wrong thing. You’re worried about the grade when you should be thinking about whether you have really truly 100% mastered that material. If you didn’t have time to learn it or it wasn’t taught well, odds are you haven’t, and remedying THAT deficiency needs to be your priority.
You have options on how to address that. You can find a summer course. You can ask your new counselor (and head of the math department) at your new school to advise you on what to do. Again, you need to understand that your problem is not the grade but a possible gap in your math foundation.