Watch case backs take a beating!!! 20 years of practice, specialty tools and a sharp eye, I can undo some damage but not all. Damaged case backs like this can be easily prevented with better quality tools.
A two pronged tool is by far the most dangerous! A tool like this is the number one cause of damage to case backs from slipping.
This tool is the next step up. Much safer but still risky. This tool can be used safely with a steady hand and some skill.
This is a Bergeon Watch Case Opener; what a watchmaker would use. I would recommend having a watchmaker open your watch to prevent damage. Inconvenient? Not nearly as inconvenient as sending me your case back to be repaired!