Pinterest app missing and restricted on iPhone after update

My sister has to ask for apps. She updated her phone and pinterest disapared from the homescreen and search. She opened the app store and Pinterest said open, once she pressed it it said cant open due to restrictions, but the app was already accepted by our parents. How does she get the app back?

[Re-Titled by Moderator]

Original Title: App won’t show up and open because of restrictions but it has already been accepted after update