Gender: girl
Upon searching for "S. Mejer" in the Lodz Ghetto database, no results were recieved of a female who would have been in high school during the Holocaust. When expanding the search to 'sounds like' "S. Mejer," again no possible results were obtained. At this point no further research can be conducted.
This one bugged me so much I went back to the signatures; still looking for an "S. Mejer", and I'll let you know if I find anything in the album that might have a clue as to how to find her.
In the meantime, I do hope you find a student whose trail you can follow--hang in there, and good luck.