I'm not sure, but its my understanding that corn snakes just change colour over time. Like my snake is an anery, so from what I've read, he will most likely develop yellow down his sides and chin. I saw one post somewhere where someones corn snake was getting specks of green colour. I'm sure its just natural. Lestat just shed last night so I'm actually about to take him out now to see if he has any colour change =] this link might help you out a little
http://pets.blog.my/2011/04/why-is-m...anging-colors/