Deleted 600mb Partition on Bootcamp-ed MBP while logged into Windows 8 using Disk Manager. No longer boots into OS X On Mac Book Pro retina ( 2014 ) Mavericks running Boot Camp, one hard drive partitioned to dual boot OS X and Windows 8. 

While messing on Windows 8 I mistakenly deleted a partition which is now showing unallocated 621 MB, using Disk Management. ( it was showing a weird phantom SD drive which i thought was some improperly mounted ).

OS X won't boot and won't show in Boot Camp. Cmnd + R goes into internet recovery. My main data HD Mac partition is fine and accessible ( can copy data at least to backup my files).

I never attempted any formatting and stopped a Windows partition recovery utility as i googled further and turned out it is(maybe) a bad idea.

How can I recover this partition/get back into OS X without losing data, having to reinstall both OS X and Windows? 

Edit: Just run diskutil list and this is what I get.
Presumably you deleted the recovery partition, which is about that size. Boot into Internet Recovery, start the terminal and type diskutil list. If the OS X partition is still there, you should see it as formatted with CoreStorage (OS X doesn't require the recovery partition for a normal HFS+ formatted partition). If it exists, then the solution is to do a reinstall of the OS. This will not erase anything, but it will recreate the recovery partition. Note that you'll have to unlock your disk first if it's locked by FileVault 2.

Lesson for the future: Windows doesn't know anything about CoreStorage volumes, even with all the BootCamp drivers installed. Do not trust anything you see regarding your disks from within Windows, unless it identifies the disk as a format it knows.