No matter what happened to your camera photos, stop using this camera, especially the inner memory card. In your case, anything new on the same memory card would erase your needed photos and make them gone permanently. So, you should take care.
And then connect this memory card to your computer via a card Reader and select a proper data recovery program to take a chance. Nowadays, there are many professional data recovery programs that are developed to help the user retrieve their inaccessible data back.
Just search some efficient memory card data recovery freeware online: http://geeksdo.com/f...a-recovery.html
At last, after the data recovery process, not forget to back up all your restored photos on a different drives or memory card in case of data loss.