Stop calling it a failure and call it the first draft. Drafts are supposed to have red ink.

Calling something a failure closes it; calling it a draft keeps it open. The same result gets a different verdict depending on whether you treat it as final, and only one of those descriptions leaves you something to do next. Drafts are supposed to be marked up, since that is what they are for. Nothing about the work changed, only whether the story about it has an ending.

Take whatever you are calling a failure and write down three things the next version does differently. Keep the old one rather than hiding it. Start the next draft while the notes are still warm.