My question is, just in case, how do I revert back to the old firmware if I choose?
Just flash it. If you're using an official LiteOn flasher, you may need to use FlashFix first. But otherwise, just flash.
Does it matter which order I restore things (EEPROM and firmware)?
My burns are getting worse and worse
If the burns used to be good and they're getting worse, a firmware upgrade will unlikely be of much help. Try resetting the media learning. Or maybe even lens cleaning.