If you downloaded the note, search your "Downloads" folder for a .txt file with that date or timestamp in the name.
Many sites auto-save notes to your browser. Revisit sites like JustNotepad or Evernote Online to see if the text is still in the editor. Note 11/15/2022 2:31:41 PM - Online Notepad
If you shared the note, check your sent emails or messages for a unique sharing URL. If you downloaded the note, search your "Downloads"