Go to your My Files in your computer. File Explorer > Documents > Unreal Projects > Project Name > Content. Find the object you were editing when the crash occurred, then delete it. I know it may suck getting rid of it, but worst case scenario, you still have the rest of your game. This same thing has happened to me countless times throughout this project I am working on.
Once you delete the object, of course it will need to be recreated, but it will allow the editor to open up without any issues. And for the future, ensure that once you get this working again, you make a backup copy of your game. This will come in handy for whenever you cannot get your project back.