How undead looking is an "undeadlike creature"

Mummification (Ex): The alchemist has mastered preserving flesh and applied this knowledge to his own body, turning himself into an undeadlike creature. After learning this discovery, the alchemist must perform a 30-day regimen of a special diet, rigorous exercise, and drinking a mildly poisonous alchemical tea. At the end of this regimen, he falls unconscious for 24 hours, then awakens as a “living mummy.” The alchemist's type does not change, but he becomes immune to cold, nonlethal damage, paralysis, and sleep. An alchemist must be at least 10th level and must have the preserve organs discovery before selecting this discovery.

How freaky do you look?

I just sort of think of it as how the dude from the "Mummy" movie franchise looked when he was feeling all filled up on lifeforce or dude-eyes or whatever.

Just sort of like a dude who has undergone laser hair removal and done his GTL appropriately

Mummification (Ex): The alchemist has mastered preserving flesh and applied this knowledge to his own body, turning himself into an undeadlike creature. After learning this discovery, the alchemist must perform a 30-day regimen of a special diet, rigorous exercise, and drinking a mildly poisonous alchemical tea. At the end of this regimen, he falls unconscious for 24 hours, then awakens as a “living mummy.” The alchemist's type does not change, but he becomes immune to cold, nonlethal damage, paralysis, and sleep. An alchemist must be at least 10th level and must have the preserve organs discovery before selecting this discovery.

How freaky do you look?

As far as I can tell, you look normal. Nothing in the paragraph above says otherwise. Given that vampires, full blown undead, also typically look normal enough to interact with civilized society, I don't see this as being that unreasonable.

I think you would look...

Maybe a bit dehydrated? You're not dead, not even close to dead, you certainly would not look like you are rotting

I imagine your flesh would look a bit dessicated and stretched on the bone, and your skin tone would be slightly yellowish- or brownish-gray.

Mummification usually involves a corpse being preserved in a dry location. Google "Sicilian mummies" or "Incan mummies" for some ideas - but since you are still alive, far less extreme than those.

E.g.
http://whirledview.typepad.com/whirledview/images/2007/03/15/mummy.jpg
http://interestingincas.webs.com/inca-mummies1_1822.jpg