Is there a way to fix any rating I gave?
Your query is not clear. Will you please explain what exactly you want to know.
You mean, the rating you gave as a buyer? For example, you mistakenly gave a lower rating than intended? No, you can’t change it. And if you contact Customer Support and ask them to change that rating for you, they will accuse the seller of feedback manipulation (sellers aren’t allowed to mention reviews at all, or to try to make the buyer feel bad about the rating they gave them), and give the seller an account warning.