That shouldn’t normally hurt anything, as far as I know. I’ve done it numerous times with no ill effects.
I have to ask the obvious though. Did you power down / reboot the Pi after that happened with the HDMI in Port 0?
I have one monitor that for what ever reason won’t see my Pi 4B if I plug the monitor in after its booted up? If I plug it in and turn the monitor on first, no problem.
A static discharge wouldn’t be good if that’s what happened.
Do you have another monitor to try with that Pi?
Or another Pi to try with the not working monitor?
That would tell you which device stopped working.