Bay Area rapper Sky Balla, who's worked with Mozzy and E-40 is being held in Las Vegas on $1 million bail after a brutal sexual assault.

A woman says she met Sky at the Aria casino bar last month.  They did a couple of shots together and she says she blacked out.

She awoke in a hotel room in severe pain as Sky was raping her.  When she told him to stop, he repeatedly punched her face until she blacked out.  When she came to, he was forcing himself into her mouth.

She says she then crawled in the shower and hide amongst her blood for two hours until he finally called her an Uber.   She immediately went to the hospital where she got surgery. A few days later, a friend convinced her to go to the police.

The police were able to identify Sky, 41, because a photo the victim had of him matched some of his music videos on YouTube.

There was so much blood in the hotel room she was attacked in it's been shut down as a biohazard.

Sky, who's already a registered sex offender in California, is now facing charges of sexual assault resulting in substantial bodily harm, battery with intent to commit sexual assault, and more.  He's next in court on July 13.