Hello,
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The description of the lump (Location and the tenderness on pressing it)indicates it to be a enlarged lymph node, associated with a transient infection in the dentition or in the nasopharyngeal region.It does not seem to be anything serious.
You can take a few Over the counter anti-inflammatory medications like Motrin or Advil for a few days. This will help in resolution of the node.Along with that ice pack application would also help.Kindly continue with that.
If the pain increases,any change in size occurs or there is development of any other symptom then consider visiting a Physician for evaluation so that if needed a course of antibiotics can be prescribed to help clear any infections. In case of doubt,you may be to undergo a biopsy of the lymph nodes for a definitive diagnosis.
Let me also explain you that symptoms like persistent fever, weight loss, night sweats along with multiple enlarged nodes are indicative of cancer.
Take Care!