Sam ~ You can probably express this in a more concise manner ~ something like this might work without changing the essential meaning:

"He's upset because initially he was not approved on the exam, and subsequently, he chose to measure his performance against the performance of the best student in the class."

Hey, your sentence isn't grammatically correct. That's ok though, try your best.

You could say the following instead:

He's upset because he didn't pass the exam. After finding out, he got even more upset when he compared his grade to that of the number one (or top) student in his class.

Nice