You can click on your "pro-gamer's profile" on the top right corner of the site and then click on "Status & Badges".
From there, you can see how many best answers you've got.
It doesn't show the ones, but just how many.
if it was a recent best answer, then you can just go into your profile and click on "Access to the whole list of his/her messages"
From there, you can specify the section and find it. If it was a best answer that you've gotten earlier, then it might not be displayed there.