The only thing I can recommend for a quick solution is the following.
- Launch the game, go to Options.
- At the very bottom, find the Debug option.
- Activate the debug/cheat panel.
- Save the settings and exit to the main menu.
- Load the saved game.
- In the lower left corner, a fifth button should appear - DG. Click on it.
- In the window that appears on top of the game, select Open character creator.
- Recreate the character the way you want him to be (ideally with a permanently flat chest, if that's what you want). You will be able to continue the game with the recreated character, he will not lose any skills, characteristics, etc., this will not reset the game world.