If you have a mole that's suddenly sprouted a friendly strand, you're in good company — dermatologists say that's a common experience. "Typically, moles that are raised up from the skin and have been present on your body for some time will have hair growth," said Dr. Greer. Luckily, hair growth alone is not a sign that your mole is dangerous, but if you notice it in tandem with your mole changing colour, bleeding, or increasing in size, you might be showing symptoms of skin cancer. To be safe, consult a dermatologist as soon as you can.