Lightroom 4 collections/book issue

[12sndsgood]

Okay making a book in lightroom of my latest work. I made a folder with all my automotive shots. then went into book mode and laid out a book. I'm sure I did something in between when I left to take my kids to cub scouts. I just had to make a cover photos so I went into photoshop, added my logo to a photo, then saved it into my automotive director for the book. I then went back to lightroom to syncronise the photo. I did this for a couple of pohtos. but. but now if you go into collections its showing not showing any of the new photos ive added and i'm not sure what I may have did. could it be that I saved the book when I left? does that lock it so no more photos can be added? help me out. this book is done except for this one single cover photo lol.

 

[12sndsgood]

anyone? Bueller? Bueller?