Apparently, her name was Carla.
The diarist's name is Carla. On p. 113 of the novel, While having sexual relations with a man who deals her drugs, his son yells to his mother, "Mama, Daddy can't come now. He's humping Carla." This is the only time in the book that she quotes someone else speaking about her. Alice is not the protagonist's name.
http://en.wikipedia.org/wiki/Go_Ask_Alice#Diarist.27s_name
In my book it's page 97. share