What message do you want to convey? To show the complexity of a process, you can make it look complex by adding all the feedback loops, failure paths and exception handling as possible.
This is probably not what you want.
Focus on making the core, original, process as readable and easy to understand as possible by all stakeholders.
Feedback loops or failure paths are these arrows telling you where to go back when an activity has failed. I usually discourage users from capturing them at all. As a general rule, people acting on a process will figure out where to go back if a problem arise.
Exceptions are different, sometimes a process need to be followed if an activity fails. In this case, i usually encourage to map these exceptions in lower level of details to not clutter the higher level processes.