If you did your best to write a complete, clear, and insightful essay within the time allotted, you should have nothing to worry about.
For this reason, it can be helpful to simulate the conditions of a timed exam before the actual day: pick a practice question, find some lined paper, set a stopwatch, and see how you do!
Unless if you finished way ahead of schedule, don`t worry about major revisions like reorganizing the structure of the essay–it`s better to hand in an essay with an imperfect structure than a paper that`s impossible to follow because you had to stop halfway through the revision process.
Come up with a thesis: The thesis is the central point or argument that you want to make. A clear thesis is essential for a focused essay—you should keep referring back to it as you write.
Without a clear plan, you run the risk of realizing partway through that you`ve drifted off topic or written yourself into a corner, and fixing these mistakes will consume a ton of extra time.
The body of your essay is where you make arguments supporting your thesis, provide evidence, and develop your ideas. Its purpose is to present, interpret, and analyze the information and sources you have gathered to support your argument.