Oh and aside from Self = Local
You can do a Get Rotation action. You area already identifying the parent object some how... because you are setting an object to be it's child. Right? So do a Get Object using that same reference.
OR
If for some reason it's hard to get that reference. Another way to do it (once you have the object already a child) is to do a Get Parent on the throwing object. So yeah, once you identified that parent, do the Get Rotation.