let the genie out of the bottle

let the genie out of the bottle (to allow something bad or unwanted to happen which cannot then be stopped; to do something that causes a situation to change, so that it is no longer possible to go back to an earlier state) — выпустить джинна из бутылки
If people let the genie out of the bottle, they let something bad happen that cannot be put right or controlled.

Example 1: With the Internet, we really let the genie out of the bottle. People now have unlimited access to all manner of material. (Cambridge Idioms Dictionary)
Example 2: Now the press has let the genie out of the bottle, the question is what happens next. (MM)
Example 3:

the genie is out of the bottle (something has become known) — джинн выпущен из бутылки
The idea is that something has been done that cannot be undone.

Example 1: Efforts to ban cloning cannot succeed - the genie is out of the bottle. (Cambridge Dictionary of American Idioms)
Example 2: ...

If you say that the genie is out of the bottle or that someone has let the genie out of the bottle , you mean that something has happened which has made a great and permanent change in people's lives, especially a bad change.

Related vocabulary:
[what is done cannot be undone]
[you can't unring a bell]
[сделанного не воротишь]
сf.:
[слово не воробей — вылетит не поймаешь]
что написано пером, не вырубишь топором