It has been concluded, Darth Sidious has masked his true form using the force. Here is the evidence that should put a firm end to this hotly debated topic. 1. George Lucas intended for Sidious to be corrupted by the dark side and decided it be shown progressively. However, this proved to be impractical so he decided to go with 'mask' idea; in which the mask literally melts away when using force lightning. This explains the discrepancy between his AOTC and ROTS appearance; the latter of which, he looks rejuvenated. Also, if the force lightning deformed his skin, did it also coincidentally deform his eyes as well, making them a typical Sith yellow? Did it make his voice coincidentally sound evil? Why didn't the force lightning destroy his clothing? How did he recover so fast? 2. Derek Thompson: writer of, Sithisis. Had multiple interactions with, George Lucas. And, Ian Mcdiarmid. After consulting both, he ventured further into ROTS based on their information and developed the ritual behind the mask theory. Even though this is EU material, it confirms Lucas' intentions: "Drawn by the Force"—Star Wars Insider 82 3. Star Wars insider 82 confirms the mask theory; Star Wars insider 83 confirms the mask theory; Ian Mcdiarmid confirms the mask theory. 4. Canon comic books directly and indirectly support the mask idea: This page from the Lando comic book series indicates the dark side does indeed cause corruption; this royal guard merely spent time in the presence of Sith artifacts. This image from the new Maul comic shows Palpatine's appearing deformed and corrupted; despite the events of the movie predating TPM. 5. No other victim has been scarred by force lightning: Luke Skywalker, Mace Windu, Darth Maul. I hope this can clarify the awful myth of Palpatine being scarred by his own force lightning, this is unfounded and contradicts many canon sources. I hope we may finally lay this debate to rest.