How do we distinguish between the whispers of Satan and the whispers of the self, and is a person punished for the whispers of the self even if they reject them?

Not all intrusive thoughts (waswas) are of the same degree. Some originate from the soul that inclines to evil (an-nafs al-ammarah bis-soo'), or from the devils among jinn, or from the devils among humans. These are intrusive thoughts that disappear with seeking refuge in Allah and strengthening one's connection with Him. As for obsessive-compulsive disorder (waswas al-qahri), it is a pathological condition for which a Muslim is not held accountable, because it is beyond their control. It indicates the soundness of one's faith if the Muslim dislikes it and struggles against it.