Hi Dear, Welcome to Health Care Magic Team. Understanding your concern about health. Purple colored mole like growth on your neck could be because of excessive pigmentation of melanin in that area. It could be deep lying mole and purplish appearance is due to red vessels of overlying skin. Hyper pigmentation could be the cause. As this area is tender to touch, and its size/ number keeps on changing like increasing or decreasing then you should consult your dermatologist immediately. Many skin diseases like melanoma also gives the same appearance. Dermatologist will take specimen from that area and after doing tissue biopsy will find out the exact diagnosis for your condition and treatment can be started accordingly. Hope your concern has been resolved. Get Well Soon. Best Wishes, Dr. Harry Maheshwari