My daughter has had a knot to come up behind her ear on her head. it's hard and about the size of a marble. she said it hurts to touch it. ?

Mgt: She may have an infected lymph node, and if confirmed can be treated with antibiotics.

Lymph node: Solo or several enlarged nodes in the neck are usually reflective of a local process. Irritation of the scalp, a local bug bite, etc.Nodes are usually pea sized ; run a 3-4 week cycle of enlarging when stimulated, processing their irritant and returning to resting size. If continuing to enlarge, painful or persisting in an enlarged size after 3-4 wks, they need eval.