Camera problem after rear replacement

My girlfriend cracked the rear of her phone but unfortunately one of the cracks went over the camera viewer.

I ordered a replacement cover from eBay and had it replaced in a shop for a small fee.

During the evening she noticed the camera was struggling to focus and the pictures seemed 'off' so I took one with the flash and it looked like the picture in the link

http://imgur.com/wjHIUc6

To me it looks like there is still a cover over the viewing hole but I'm unsure. Has anyone else had any problems with the camera after a back replacement? Or any idea what else it could be?