Actually when sebum gets trapped in a duct that has no opening on the surface a hard white lump appears. Milia (whitehead) usually affect dry skin and they can also appear after some damage has been done to the skin. unfortunately, if you have had these for some time they will need to be removed by a beautician. But recently formed milia (whitehead) can be dispersed by massage. Use the following:
Bergamot 5 drops
Thyme linalol 5 drops
Diluted in 1 tablespoon of Coconut oil
Use a very small amount of the oil to massage the milia (whitehead) twice a day, in the morning and at night. This will allow the milia (whitehead) to be reabsorbed by the body.