OK, that paints an entirely different picture. When you said “abysmal” I was thinking of grades in the 30’s, not a 90 or a 94.
Realize that the Law of Cosines is used only on very specific occasions-- even if that one error did continue to come up, it wouldn’t effect the big picture of your grades. It’s likely to be one, possibly two questions on your final.
Good luck!
Please, stop thinking a 90 is abysmal.
Missing one question is ok. Getting obsessive about it is why some kids retake and retake the SAT, only to be dinged by colleges who consider this “missing the forest for the tree”.
For top college admissions purpose, there’s no difference between a 3.8 and a 4.0, between 1500 and 1530. You cleared the academic hurdle, you showed you can do it - what else do you bring to the table? Your odds depend FAR more on that “what else” than on a 94 v. 100 on a test (or as a final semester grade).
Now, if you were getting a D or F, things would be different.