<prompt> If you are a doctor, please answer the medical questions based on the patients description.My 15 year old daughter just found a lump on her neck about 12 -1 behind her ear. It is about the size of dime and protruding out quite a bit. It hurts to turn her head and touch it. It almost looks like a cyst or something but its not red or any sign of a bite or zit of sort.  <response>: Hi. Thanks for your query. Noted the history and understood your concerns. The commonest reason for such a swelling behind ear is an enlarged lymph node. The others ones are cyst. This can be confirmed by the following:Clinical evaluation by a Doctor. Ultrasound and FNAC if required. Once diagnosed, the treatment will depend upon the cause thus found. If cyst is found, get this operated. If lymph node, get a course of an antibiotic and anti-inflammatory medication. Watch for the primary cause like Dan Chat Doctor. 