Should I talk to my professor about my grade? I just found my grades for the fall semester, in an introduction to international relations class that I took, I got a B. 

I got a 93% on the midterm, which was worth 25% of the grade. 

I always came to class prepared, having done the reading, and actively participated, so I probably got an A in participation, which is 5% of the grade. 

There was a mock UN simulation which was worth 20% of the grade that I felt my group did pretty well on, but I never got an actual score back. I made some small mistakes, but worse case scenario, I think I got around an 85%. 

My final paper, worth 25% of the grade, everyone said that it was a really good paper, and that it deserves an A, even people who took the same class from her, as well as writing tutors that I went to. 

The other 25% of the grade was reserved for quizzes that according to the syllabus, we're supposed to take place every two to three weeks. However, she only gave us two. The first one, she failed everyone, and said that she did that to scare us, and make sure that we read the material. The second one, I got an A on. 

I asked her about the quizzes, and she said that they were used for extra credit, which doesn't make sense according to the syllabus. 

I am really confused about why I got a B, and I think that she might have made a mistake. 

Should I talk to her about it when I go back to school, and if so, do you think that she made a mistake?
To expand Bob Brown's answer, yes, you should talk to your professor politely with the objective how to improve your study in the future.

In my opinion, your grade is probably on the borderline between A and B. You need to ask her what grade you got for the final paper (worth 25% of the grade). [E]veryone said that it was a really good paper, and that it deserves an A is not enough for you to say you did get an A on it. You need ask her how well was your final paper.

Generally speaking, it's not easy to change a grade after it's out of the professor's office unless there was an obvious calculation error.So, don't expect she will change your grade from B to A unless your final paper was extremely well written.

I won't be surprised if she tells you that your final paper was okay but not good enough for an A. In that case, you should ask her what you can do to improve your writing skills so that you can get better grades for the future essay writing assignments in other courses. Good luck!