Milia are white or yellowish crusty spots or raised
cysts usually found on the face that are caused by
keratin blocking
sebaceous glands or
sweat glands. If found in the mouth, they are called
Epstein pearls.
Primary milia is found in your undeveloped, freshly popped neonate and usually disappear within a few weeks. Primary or secondary milia can also develop in children and adults and may require medical attention. Milia can also rise in response to harsh skin treatments.
There is no successful proven treatment for persistent primary or secondary milia besides a doctor slicing it open and squeezing the contents out like a pimple.
Sources:
1. http://en.wikipedia.org/wiki/Milia
2. http://www.emedicine.com/DERM/topic265.htm