Mark it as an achievement on your learning path and move on. We all did something silly like that at some point.
Great that you have backups, get a fresh install and restore it.
Lessons learned: don’t work as root unless you absolutely positively have a good reason to do so.
I always treat the system as discardable and only backup the /home and /etc directories. Saving those, I can afford to wipe the system and re-settle on a new distro if I want to.
Of course if you throw Windows into the mix, all bets are off. Personally, I stay the hell away from that.