Korn Bassist Fieldy -- I Got a MASSIVE Heart Injection [PICS]

Korn bassist Reginald "Fieldy" Arvizu has turned his back on his own heart -- getting a bleeding ticker tattooed between his shoulder blades last week ... and TMZ has obtained the inky pictures.

Fieldy hit up Goodfellas tat shop in OC on Friday with his rapper pal Ditch -- and famed shop owner Steve Soto personally inked up the rock star's spine ... inscribing a melting candle "sacred heart" design.

It's unclear how much the bassist paid for the privilege, but we're told Steve typically charges around $1,200 for similar tattoos.