problem with online exam result

Hi there

Having a problem in an online exam result

For now everything is ok, user take exam and get the result immediately after the exam.

The result for each Q has the Q’s title, Q’s body and user mistakes.

Problem is about when the user want to check the exam result after for ex. 2 weeks and after this 2 weeks some Qs maybe has change, some new questions adds and some Qs were removed!

what should i do? how to solve the problem?

thanks in advanced

I guess saving questions along with answers is an option.