What are these small marks? What are these little marks on the arms of the model? 

They randomly appeared after I pressed CTRL+V in Object Mode and I cant get rid of them, it also didn't let me undo so I'm kind of stuck.
Please take a look as marked with the red arrow;


Edges is seems to be pushed back, Try Alt + Click and bring it forward

Alternatively try, wireframe mode to view the all edges, by hitting Z key in edit mode or selecting Wireframe under viewport shading.