What type of chrome paint did you get?
The best is alclad 2 and costs about 16$ a can plus shipping. It should lay right down on a well laid coat of gloss black, then usually needs to be dulled down a tad with testors dullcote, after the chrome is thoroughly cured.
BUT most of the helmets you see are coldcast resin that contains an aluminum powder and polishes to look like metal. Some are rub and buff silver leaf which can also be made to look outstanding, and costs like 5$ a tube.