Gonna need to do a bit of guessing here because we’re lacking info about your BP’s hierarchy and how exactly GPMesh is initialized. Seeing as it’s a component (based on the GetOwner function call), I think your hierarchy is similar to this:
If that’s correct, keep reading. If not, correct me with some extra info. 
Assuming this is correct, we need to clarify some terminology first - GPMesh is not an actor in this case, it’s a component of the actor whom you’ve described with your blueprint. That’s the same actor you’ll get when calling GetOwner on GPMesh; meaning, if you then SetActorRotation you’ll rotate the actor and (consequently) all its components. If you just want to rotate a single component, for example GPMesh:
- replace the
GetActorLocationcall withGetWorldLocationand pass in the component directly - replace the
GetActorRotationcall withGetWorldRotationand pass in the component directly - replace the
SetActorRotationcall withSetWorldRotationand pass in the component directly - the new node will have a Rotator input instead of XYZ, just split the Rotator using “split struct pin” (see image) and connect your green wires
