显示 it anyways. Grades aren't everything and your life isn't over. If they're mad, they're not going to be mad at 你 forever, in fact, its nice they care about your education. Its better to deal with the disappointment now than worry about it any longer. It might help 你 to study now for the 下一个 exam.
显示 them the results. They'll find out somehow anyway and it will look better coming from you. Try and explain why your grades went down - have 你 been having difficulty in lessons?