This is a tricky one... This is my suggestion of what I would do in this situation, please note that this is just my opinion.
I would say notify them all that you will be re-taking to avoid looking sneeky. (You don't want them to find out that you re-took it 'behind their backs', or looking like you don't want them to see the new score)
Also, for the re-take, take it as soon as possible. You want them to see your score before Dec. 1. Try to get in asap.