Mickey Rourke -- My Dog Will Live Forever

Mickey Rourke will never forget his deceased dog, even if he wants to ... because its nickname is now emblazoned on his arm.

Rourke paid homage to his four-legged buddy Jaws at a New York tattoo parlor Sunday night ... where the actor sat for 2 hours as the artist inscribed the dog's nickname, "Guapo Siempre" -- handsome forever -- on Mickey's arm.

It appears the Chihuahua went to dog heaven in the last few months. Mickey was emotional during the session, showing the tattoo artist pics of Jaws and telling stories about the tiny pooch.

The ink set Mickey back around $400, plus a big tip.

You may recall ... Mickey lost Loki, another chihuahua, a few years back, and it really broke him up.