If you will excuse the pun, your sentence presents a perfect example of the present-perfect. The time (some point after the test) is considered in the present, and the test's "going" is complete. Therefore you write
After an exam has not gone well, she just goes ahead with renewed zeal.
(Incidentally, you are using the same word, go, in two different senses. That borders on syllepsis and is probably not a good stylistic choice in any language. How about "she carries on" or "she returns to work"?)
Edit: In all the cases I could think of, the aspect of verb in the subordinate clause has to match the main verb, even where it patently makes no sense.
After he exercises, he showers.
Logically, it should be "exercised", because it happened before the present-time of the shower -- but no native English speaker would say "exercised" in that context. At most, you can use present-perfect, "after he has exercised".
What can I tell you? English is weird.