More details have emerged about Chris Brown’s alleged assault on Rihanna, with law enforcement sources describing Rihanna’s injuries as “horrific.” Photos reportedly show serious swelling and bruising, a split lip and a bloody nose, as well as bite marks on one of her arms and on several fingers. Radar Online reported that a eyewitness saw Rihanna being treated for her injuries at Cedars-Sinai Medical Center early Sunday morning. “Rihanna was brought through the back entrance on a gurney, flanked by two LAPD officers,” the source said. “She was clearly very upset by what had happened and I could hear her screaming. She sounded like she was crying as she tried to get to put her point across.” Brown reportedly fled the scene of the incident on foot with the keys to the silver Lamborghini they were driving in, leaving Rihanna “beaten really badly and hysterical” by the side of the road, a source told E! Online. “Rihanna didn’t want anyone to touch her, she was in so much pain.” Brown and Rihanna, who had been dating for a year, were on their way home from Clive Davis’ annual pre-Grammy party on Saturday night prior to the alleged incident. Meanwhile, Rihanna has cancelled her February 13th concert in Malaysia.