Nothing. You'll have to restore a backup of the rooted version. If you never made that backup, you know now that, before you do anything major, you make a backup. Even if nothing goes wrong and you delete it later.
For now, all I can suggest is that you follow the same procedure you did to root it (probably from XDA?), than reinstall all the missing apps. (And if any of the apps had data in them, it's gone.)
You're not alone - after 46 years of designing computers, you'd think I never make a mistake like that, but I have - a couple of times this year alone.