Boot Camp Partition Broken after Partitioning and can't be Repaired in OS X 10.9.5 (on Macbook 13" Air - Late 2014)
Did you make a bootable Windows installer USB key?

That one item would be key (no pun intended) you should be able to boot from the USB key. Then you should see the current partitioning. Hopefully your Mac and Windows partitions are still there. If not you are likely out of luck. You should be able to continue through this and boot into the Windows installer. Once you have gotten past the language and keyboard selection you should be given an option to install or repair Windows. Select repair.

If you do not still have the installation media you may want to create it again. I assume the Mac side is till working or you have access to a Mac. Just run the Boot Camp.app and when it asks for a Windows ISO point it to your Windows 7 installer, the one you used before, and let it do its thing.