If I forget how to write a character during the HSK, can I copy it from the supplied exam materials?
I remember when I was in middle school 语文 test, I forgot how to write a character, I jumped to following questions, then occasionally I found that character in question descrpition. That moment..., it is like I found Blackbeard's treasure.

I don't think it is cheating, it is a gift. No one would stop you to look at your exam paper and copy them.