Can I remove the boss from the map after he appears using Oblivion cards by reducing the map progress bar?

When playing the game, you progress in a map by placing tiles. This fills a progress bar for map completion where the boss appears when this is filled. This bar increases when you place new tiles on the map and decreases when you remove them using Oblivion.

Suppose I was not ready for the boss yet and accidentally fill the map progress bar (because I wasn’t paying attention), could I use Oblivion cards to remove the last placed items to "revert" back to when the boss had not appeared?

I know I cannot remove the boss tile this way so that’s not an option.