“Everyone else did worse” is a comfortable blanket. It doesn’t change your score.

Comparison changes how a result feels without changing the result. A low mark in a class that all did badly is still a low mark on your paper, and the comfort of the group average lasts until the next test, which will not care. Comparison is not useless, since it tells you something about the teaching or the exam. It just cannot do the job of looking at your own work.

Read your paper before you read anybody else’s. Find the two or three questions you could genuinely have got and work out what went wrong in each. The class average is a fact about the class.