There should some auto-saves of the project content. You can try to remove the broken asset (the BP causing the issue) via file browser and then open the editor again. Depending on how recent the problem area was created in regard to the crash, you could start with the most recent version (chances are it will be identical or nearly identical) or with hopes of having multiple auto-save versions, you would start by going back to a later save; the steps to start with is by making a copy of the auto-save file and moving it over to the original directory\path (either overwrite or if its already been removed then just paste) and followed with trying to open the editor again. If it fails, simply repeat the steps going with an earlier version of the auto-saved file each time.
Default UE4 Project Directory
C:\Users’Username’\Documents\UnrealProjects’ProjectName’‘SameAsEditorContentBrowserLocation’
Default UE4 Project Auto-save Directory
C:\Users’Username’\Documents\UnrealProjects’ProjectName’\Saved\Autosaves\Game’SameAsEditorContentBrowserLocation’