No, you're not screwed and there's no need to do a restore.
I use the following script that 'sys-preps' a mac ready for deployment. You can use it if you like (at your own risk) but obviously change it to suit on the workstation you're going to use as your deployment model. Apple calls this the 'Golden Mac'.
I'm assuming the following:
1. The local administrator account's short name is localadmin (change this to suit). NB if it was me I would make sure there is only one local admin account.
2. There are no student accounts or there home folders stored locally. My assumption is they're all logging in over the network (ie: Open Directory)
3. Printer(s) are configured as you want them.
4. All the software/apps you want the students to use are already installed.
5. Everything, including the OS, any other Apple updates as well as 3rd-Party apps or software etc is up to date.
6. If the macs are up to date then as a just in case, download the full combo update for the OS version you're on and install on that one workstation.
You only need to do this on one mac. You can run what follows (simply copy/paste) in ARD's Send UNIX Command window.
rm -R /var/db/BootCache.playlist
rm -R /var/db/volinfo.database
rm -R /var/vm/*
rm -R /var/vm/sleepimage
rm -R /System/Library/Extensions.kextcache
rm -R /System/Library/Extensions.mkext
rm -R /System/Library/Caches/*
rm -R /Library/Caches/*
rm -R /Users/localadmin/Library/Preferences/ByHost/*
rm -R /Users/localadmin/Library/Caches/*
rm -R /Users/localadmin/Library/Saved\ Application\ State/*
rm -R /Users/localadmin/Library/Preferences/com.apple.recentitems.plist
rm -R /Library/Preferences/SystemConfiguration/*
rm -R /Library/Managed\ Preferences/*
rm -R /Library/Preferences/OpenDirectory/*
diskutil repairPermissions /Volumes/Macintosh\ HD
reboot h now
You can miss out the the last reboot command if you wish as a simple manual restart will do the same thing. However, remember the first golden rule of IT: "If you can do it sitting on your a@*e then do it as it's better than walking." Don't worry if some of the commands return an error. These will be harmless as some of the folders/files won't be there. Remember to send it as Root!
So what does the script do?
Basically it 'resets' the mac back to a state where it's nameless (there's no name in the Sharing Preferences Pane) as well as removing any cached data and settings specific to that machine and users(s). It also removes any bindings you may have to either Open Directory and/or Active Directory and locally cached managed preferences applied by WorkGroup Manager. Finally it repairs permissions for the drive.
Once done and assuming you're using OS X Server's NetBoot Service and Deploy Studio to first; capture the image and second; deploy it to the rest. You can use Deploy Studio's powerful workflow interface to give all the workstations a unique name, set the date and time server for SSO authentication as well as binding/joining Active and/or Open Directory.
But before you capture the image and after you've ran the series of 'sys-prep' commands I would prepare another workstation in the same way. Then login to the prepared workstations. Enable Remote Management - remember to tick all the options - and try sharing your screen with the two of them. Hopefully that may 'cure' the problem?