Facebook and Twitter have both made efforts to take the photos of the girl, from the west of Ireland, off the internet.
But the distraught teenager is already under hospital treatment after the images flashed around the world.
Police have confirmed to the Irish Independent newspaper that a ‘major investigation’ is now underway after the images went viral online.
The girl has also claimed that she was sexually assaulted at the concert although the paper says the incidents are not related.
The girl has yet to make a formal complaint about the photos which were taken in broad daylight in a public section of the Slane venue during the sell-out gig.
Hundreds of internet users shared the graphic photographs on Monday before a public outcry in Ireland led to Facebook and Twitter attempting to remove them.
Facebook has closed down one page which published the photos and has threatened action against others.
The parents of the secondary school student are said to be devastated.
They were contacted by police on Saturday after the girl reported the alleged sexual assault before the photos went viral.
Sources have told the Irish Independent that the girl was so distraught she had to be sedated in hospital on Monday.
One source told the Irish Independent: “The primary concern for gardai (police) at this time is for this vulnerable teenager and her state of mind.
“Gardai have been dealing with her and her family. This is a very sensitive case.
“The teenager has not been medically fit enough to make a formal statement yet, but when that happens this could turn into a sexual assault investigation.”