Friend deleted app (my disk for iphone) and need to get back data from my icloud backup...need help!

I had this app called my disk (app store name is: Lock photo+video safe - secure folder manager to protect private photos vault & hide secret picture file privacy) This app lets me have two passwords with different pictures and videos in each of them. It's a really great app.

My friend deleted the app by "accident" and I need to get the app back with all my data. I have a backup of the app on my icloud backup that was taken place two months ago (around same time the app was deleted). It shows up in the cloud saying I have 4gb worth of that app in the cloud. I restore my phone back to that backup but the app data is not there. I wasn't sure if I had to wait till my iphone backs up everything (like music and pictures for example) for it to show up but as soon as the app downloaded I opened it hapilly knowing I have my data back but unfortunately it was not there. In the app itself, there's an option to backup from the cloud but it just brings up this window that says you can back up from the cloud (doesn't have a place to hit that says restore or anything).

Is there something I am doing wrong? Can anyone help me? I really need that app data back because I have pictures of memories with friends and family inside that app that I do not have anywhere else. Once i get the back back ill be sure to save the photos onto my computer just incase anything goes wrong again.

Thanks everyone for the help!

Nikhil