<s>[INST] My son has a lump on the side of his neck that is very close to his jaw line where his jaw meets his ear, about one inch in diameter, pink in color, hard composition, and painful to the touch.  Any ideas as to what this might be?  My son has no known allergies but did have dental x-rays this morning for the first time.  Could this be a reaction to the radiation? [/INST] Hi, Welcome to Chat Doctor. This could be Mumps Parotitis with preauricular lump in your sons neck just closet the jawline, as its painful and hard. This is not a reaction to the dental x-ray which your son had. Other possibilities need Second opinion from a Surgeon. I would hence suggest consulting a Surgeon and if need be decompressed the painful lump. Hope this would help you to resolve your query. Else Contact with a Followup Premium question to ME. Will appreciate your Hitting thanks and writing excellent review comments to help needy patients like you. Welcome with any other further query in this regard. Good Day!! Chat Doctor. S. Genl-CVTS </s>