Unless a medical provider could examine you first-hand and take a detailed medical history, it would not be prudent to make a blind guess over the Internet, as to what this lump might be. A picture is not helpful, unfortunately. A medical provider would need to carefully examine not only this lump of concern, but examine the entire area from the neck up. It could be a lymph node, cyst, or yes, it could be a sign of a serious mass -- one that may need to be imaged (CT or MRI) or perhaps, even biopsied. You cannot make this determination from a photo or a vague description.
You are the trustee of your body. It is your responsibility to take this seriously and be properly examined.
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