I made a similar learning when messing with PAM to enable TouchID with sudo on a Mac!

Edited the config with "sudo nano /etc/pam.d/sudo", a typo slipped in, saved the file and closed nano. After that sudo was broken and I had to go down the rabbit hole of changing a root owned system file without sudo to fix it.

The next time I opened a root shell with "sudo -s" and THEN opened nano. Made absolutely sure sudo still works in a new Terminal window before closing anything.