I created C++ class and blueprint class based on it. When i place BP to scene and try to edit bp class for this actor it also changes BP in content browser and other actors based on this class. Maybe should i create child blueprint classes before placing it to scene?
Anything you change in the main blueprint should affect anything using that blueprint including children. Are the changes you are making fundamental using C++ or inside of the blueprint? If the changes are being made inside of the blueprint directly, making child blueprints may be what you need.
Any additional specifics or info you provide may go a long way in solving your problem!