Lost a layer

I'm currently working on a project and just lost weeks of work because one layer has gone blank. 
I was using the app and had another app running in Picture in Picture. I pressed my home button to close the Picture in Picture and went back to fresco when it automatically started saving the project. 

when I reopened it one layer was blank. I unfortunately hadn't duplicated this and the one I have saved will put me back weeks of work.

Please help me get this one layer back. My project is titled WIP