Assuming you have tried to change the vSwitch Label back again.
Therefore have you tried vSphere Networking Rollback from the DCUI to reset the management interfaces on the host?
- Edit settings for the VM(s)
- You will see the network is blank
- Change to the correct network
As you said, the VM continues to run but the label is gone so in the client you do not see the network configured for the VM so have to change it as per the above,
I hope this solves your problem
You can restart your management network in SSH mode.
Log in as root
# services.sh restart