I have a mole in the back of my head, and when I brush my hair it starts to bleed. What shall I do?

You should make an appointment with a board certified dermatologist to evaluate and remove that mole if necessary.  It should be sent for a biopsy and have a pathologist look at the mole under the microscope to make sure it was a normal mole and not cancerous.    This could be covered by insurance if you have it.

Moles on the scalp can usually be easily and inexpensively removed using a "shave excision" method. The mole is actually "shaved” off at a very superficial level just below the surface of the skin. This method is quite effective to remove moles and generally leaves a minimal scar. Almost no hair is removed or destroyed. The procedure typically takes less than a minute, and is fairly painless.Dermatologic surgeons typically do both procedures expertly and can decide which would be best for your particular mole.