As I write this fresh out of finals week, I realize I have not followed my own rule to not discuss the exam after taking it. The buzz in the air after everyone turns in their exam follows the crowd. Everyone asks each other, "What did you get for ten?" All of sudden two people exclaim in relief and excitement that they got the same answer for the tricky question, but you didn't. Great. Did you get it wrong?
Hearing about other people's answers and uncertainties only work to increase your own anxiety about an exam. Personally, being surrounded by a bunch of people who are wired after taking a test doesn't help me relax after being stressed about this major portion of my grade. Furthermore, if you spent a lot of time preparing for a particular exam, you have been under pressure for a few days. Most likely, you haven't been sleeping well or taking time for yourself to relax. After the test is the time to work on something else. It is (hopefully, if you don't have another exam) a chance to go to sleep early or finally watch an episode of your favorite show.
The important thing is, if you put in the effort and know you studied, that is the best you can do. Why frustrate yourself with something you can't control anymore? Focus on the areas you can control, such as how you want to treat yourself after sitting in the same position for almost three hours with a neck cramp.
I understand sometimes discussing a test is for reassurance. You really want to know if you got that one question right. Yet, hearing different answers from five different people doesn't decrease your worries. Waiting to verify with the answer key or after the exam is returned is better. You might not remember what you wrote as an answer; going over the key without an exam might only increase your worry.
If you must talk about the test, do so vaguely. Don't ask about specific questions or drill other people for their responses. Instead, ask a broad question. How did they feel about the exam? What are they planning to do now that they are done with it? However, if that one question is burning the back of your head, try to ask a close friend. Since they know you as a friend, they can usually console you if your stress gets the better of you and makes you freak out. Most likely, they have seen the hard work and effort you have put in during late nights at the library and weekends. A good friend will remind you that there are more important things than a single test grade, despite it feeling like the heaviest weight in the world at the moment.
Use your test stress to push you to study before and keep you going during the actual exam, but when you're done, it's time to let that worry go.