Under word count

Will I fail if my word count is 500-/+10% but I had 300 words (estimated)? I am worried because my time management was compromised while being too focused on other questions, not realising the last question was worth 40 marks. It was an exam, I revised for it, but I did not have enough time for the last question. Managed to finish everything, but I do not think it was good enough, considering I significantly went under the word count for the last question.