Assuming you don’t have HS credit for precalc, which based on an earlier post you were planning on self studying, it’s fine to drop down to precalc and actually take the course and get a solid preparation for calc.
Alternatively, you can work your butt off and get a B, but the extra work you devote to calc may impact your other classes.
Your dilemma highlights a consequence for students trying to race through the curriculum and then hit a wall because they did not take the time to truly get a strong foundation.
However, if you actually have the credit for precalc, I think you need to suck it up, because withdrawing looks worse than a B.