Billie Eilish Hit In Face By Bracelet While Singing 'What Was I Made For?'

Billie Eilish didn't want to be the "bad guy" at her concert ... continuing to sing one of her hit songs after taking a bracelet to the face.

The singer-songwriter was performing in Glendale, Arizona Friday night as part of her "Hit Me Hard and Soft" world tour ... when she sat at the front of the stage -- belting out her Oscar-winning track, "What Was I Made For?"

Watch the clip ... Billie's right in the middle of the heartfelt tune when something blue -- which appears to be a bracelet -- smacks her just below the eye, temporarily stunning her.

Fans start booing, and Billie doesn't look happy ... but, she jumps back into the song without addressing the incident -- no doubt a pro move.

Check out another angle -- nothing stops the projectile as it careens toward BE's face ... and, there's an instant look of frustration before she chucks the bracelet off the stage.

Obviously, fans throwing things at their favorite singers has become an epidemic in recent years -- with varied reactions, from Billie pushing forward to Zach Bryan repeatedly stopping his shows to deal with the problem.