You remember what a teacher said about your work longer than they do. Don’t build your whole self-image on one comment.

A single remark can get promoted to a verdict without anybody intending it. The teacher said it between two other classes and had forgotten it by Friday; you have had it for six years, and it quietly decided what you are good at. The weight it carries now bears no relation to the weight it was said with.

If one line still sits on you, get it out and look at it. Write down what was actually said, then write everything since that disagrees with it. Keep whatever is useful in it and put down the part where one passing sentence became your whole opinion of yourself.