Actually, that was his face. Though the did lightning cause some burns, for the most part, it's Palpatines actual face.
<{POST_SNAPBACK}>
Yeah.
I believe that it is quite tiring to keep false appereance for years. Palpatine always insisted that jedi did it ( aka deflected force lightning) so no one is wondering his now different appereance, plus it gives him sympathy points, and jedis are even more hated because they dared to attack so brutally against beloved Supreme Chancellor
edit: Darth Maul has yellow eyes. Dooku however isn't changed. Maybe they just thought that Dooku was cool enough already