I bought these but haven't tried them yet. Below is a link someone posted.
$0.97 Replacement Screws for Atomizers (10-Pack) 10-pack - M3*4mm thread size at FastTech - Worldwide Free Shipping
$0.97 Replacement Screws for Atomizers (10-Pack) 10-pack - M3*4mm thread size at FastTech - Worldwide Free Shipping