My Daughter Has Had A Dark Colored Hard Pointy Pimple

My daughter has had a dark colored hard pointy pimple sized bump on her back for almost 2 weeks. When I first noticed the bump it came to a head. I removed the head with tweezers but the bump is still the same size and still comes to a point but no head. It is still painful to to touch. What might it be and how do I care for it?