Is it possible to turn a B- into an A after midterm?

Hey so i just got my organic chemistry midterm back and i have a B- and its really bothering Im a A-B student but im thinkng of major in Chemistry so I CANNOT afford an ugly B on my transcript in any chemstry course. Have any of you guys every brought your grades from SO FAR when only half of the term is left. Btw B- is about 83% and a A is 93% and above.