The incident occurred while the actress, who plays Mercedes Jones in the show, was on her way into the Academy of Television Arts and Sciences in North Hollywood for a panel discussion in front of Emmy voters.
She tweeted afterwards to reassure fans, writing: "Hey guys, I'm okay :) I got a little dizzy from all the photog flashes! You'd think I's be used to it by now, still a red carpet amateur I guess. Gonna get checked out but I feel fine. Thank you for all the concern and well wishes. (sic)"
She also expressed gratitude to the press for their behaviour, commenting: "I'd also like to thank the photographers for being so professional and not taking photos of me on the ground. I truly truly appreciate it. Could have been super embarrassing."
Riley recently opened up about meeting the late Whitney Houston, saying she "almost started crying" when she approached the star at Kelly Price's pre-Grammy Awards party in February.
Glee subsequently aired a Whitney Houston tribute episode, featuring the cast singing 'How Will I Know'.
Watch the video of the cast's performance below: