LAPD Investigating Bloody Alleged Rubber Bullet Incident at Lakers Celebration

An L.A. man claims he was shot in the face with a rubber bullet at the Lakers championship celebration at Staples Center ... and now the LAPD is investigating, TMZ Sports has learned.

Here's the deal ... Manny Barrientos -- a Van Nuys native who loves photography -- told KTLA 5 he headed out to Staples Center on Sunday night after the Lakers beat the Heat in Game 6 to grab some pics of the downtown L.A. party.

But, Barrientos says when police came to break up the rowdy scene ... he was shot in the mouth by a rubber bullet, which knocked out 8 of his teeth. and destroyed his lip.

"I seen my shirt all bloody," Barrientos said. "And people around me were just like, 'Your lip! Your lip is gone! Your lip is gone!'"

"My lip, it was actually on the floor at one point. A whole little chunk of it was on the floor."

Barrientos says he required emergency care to fix the damage ... and his family has now set up a GoFundMe page to try to help him pay for the medical bills.

Barrientos' family added Manny "didn’t deserve this."

The family notes Barrientos is still in the hospital recovering.