In his autobiography CB says it was inspired by "Ida Red" which his band used to play in St. Louis. "Maybelline" was orignally titled "Ida May" and, as Amos says, retitled by Chess Records.
I have always felt that Chuck Berry's first single, "Maybelline"/"Wee Wee Hours" was the mirror image of Elvis' first single "That's Alright Mama"/"Blue Moon of Kentucky". In one case you have a white boy singing the blues country style and in the other you have a black boy singing white country, blues style. In each case, the B side is somehow the opposite. Neither can claim to be the first rock'n'roll record but with these two records it was clearly here to stay.