Colossal Failure After Domain Rename
Oddly enough you're not the first person to do this.
Dell even has a guide on how to register your DC back into DNS.
You really should review everything though, a domain controller is the key part of your infrastructure that needs to be consistent and reliable.
Renaming a DC is something I've avoided at all costs in the past, and reluctantly executed with a lot of mistakes / problems that I wish I never had to resolve.
Take system state backups before each action, and verify each action extensively. Don't start deleting stuff at random!