How do you backup a skin?
Using Jamroom
Depends on how you are developing your skin. If you are doing it via the file system and adjusting files via SFTP in the /skins/(YOUR SKIN)/ directory then there are version control systems that you can use to keep track of changes.
If you are adjusting the template via the ACP via the TEMPLATES -> template.tpl -> MODIFY then there are no backups unless you've copy+pasted and saved the contents somewhere.
You could revert the server to a previous state from here:
https://www.jamroom.net/perrie/hosting/backup_browser/34/id=344
But thats not just the skins, its the data too.