If you cannot unlock using Google or Smart Lock, you are facing a hard truth: (apps, photos not backed up, downloads, game saves). However, if your photos were synced to Google Photos or files to Google Drive, they will return after login.
John laughed, feeling a bit better about his mistake. From now on, he vowed to be more careful with his lock code. At least he had learned a valuable lesson about backing up his important information... and writing things down. I forgot my screen lock code for TECLAST T50