Here’s what Pinterest says: “After you’ve published an Idea Pin, you can edit the board or section you published it to. You may notice on some published Idea Pins that comments are disabled by default. You can turn on or off the ability for people to comment on a published Idea Pin at any time.
You can store up to 100 MB of Idea Pins in draft on Android phones, store up to three GB of Idea Pins in draft on iPhones and save unlimited drafts on desktop. You can come back later to your device to finish and publish it to a board. You cannot edit your drafts across different devices.
If you’re low on storage space to save Idea Pin drafts, you’ll need to free up space on your mobile device by deleting files, pictures or apps.”
If you need to edit the title and description we would recommend to archive them to a particular board and then later make that board private so no one can access or see it on your profile besides you. And then you can re-upload them once again once you’ve done that for all of the pins.