My memos disappeared from my Samsung Galaxy Tab 4. If I press sync now will they be lost forever?

[AC Question]

My memos when I either added an app that put locks on apps and then deleted it or when I added a restricted user and a regular user account and then deleted them. Also, Gallery, Contacts, Music, and Memo was having a problem. A pop up saying that they have stopped kept popping up. It got so bad that I turned it off. Then I turned it back on and went on the Internet and my home page was back on the default Samsung site. So I panicked and thought that my contacts were gone. They wasn't. But all my memos were. (I remember I went through this with my Samsung Galaxy 5 phone with my memos disappearing. I pressed the sync now option and was told that since I did that, they were lost forever.) I synced my memos in June but I didn't see a option to back them up, so If I press sync now, will they be lost for good, or come back?