What should I do if I can't see clearly in the calligraphy exam?

It should be related.

Copying is based on the closest to the original, just like the ancients copied the preface to Lanting. In the original work, Wang Xizhi made several changes, such as adding the word "mountain" in the first line and smearing it later. The plagiarized works are all written according to the same sample.

But don't be discouraged, it's only one point short, which is already very good. Keep going!