<s>[INST] Hi, I have a spot like lump on the back of my head that appears to be infected. I also just found a lump on my neck at the base Of my hairline and there is considerable pain between these two points on the back left hand side of my head. I am 20 years old and an otherwise healthy, apart from being a bit more tired than usual lately. [/INST] Hi.based from your description, it could be a sebaceous or gelatinous cyst formation. If it is increasing in size, associated with pain and is bothering you, it is best if you consult with a doctor, preferably a general surgeon, for clinical evaluation. Other lesions must also be ruled-out. Diagnostics and management (medical and/or surgical if indications are found) will be directed accordingly. Hope this helps. Good day!!~ Chat Doctor.  </s>