Metal Face is one of the three skins released in the Rockin' Cool Skins offer. It could be purchased as part of an item deal in early March 2017.
Metal Face could be purchased for $19.99 in the limited time "Best Deal!" which included 50000 coins and the Soloist skin. This skin was not available for individual purchase and may not be available for purchase in the future.
Details of this skin may vary depending on location, platform or time.
Note: The "Rockin' Cool Skins!" offer was released again for a limited time in late September 2020. This time Metal Face, Soloist and a package of 1200 DNA could be purchased for $9.99.