It has been postulated that hair penetrates into the subcutaneous tissues through dilated hair follicles, which is thought to occur particularly in late adolescence, though follicles are not found in the walls of cysts. A sinus develops with a short tract, with a not clearly understood suction mechanism involving local anatomy, eventually leading to further penetration of the hair into the subcutaneous tissue.
If the cyst gets infected or is a problem, your doctor may need to open and drain the cyst. This procedure can be done in your doctor's office. You may get antibiotics if the infection is severe. The cyst may take a month or more to heal. You may need to have surgery (excision) to remove the cyst. Surgery may need to be done if: It gets infected again. It doesn't heal after being drained. Your cyst has more than one opening.
Many scientists are doing research in this field to give better results.