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1. The history suggests - most possible cause could be sailoadenitis ( dilated salivary glands - due to any obstruction, calculus , stricture.
2.Next possible cause could be
lymph nodal enlargement followed by vascular causes,
lipomas.
3.To assess this a simple investigation -
ultrasound scan will help us the nature of the lesion ( cystic, solid, vascular), sours of the lesion and where all its extending.
4.In case of solid mass FNAC - fine needle aspiration cytology to find out the cell type.
5.
MRI - neck also a good tool - if affordability is not an issue.
6.Suggest to see your GP and follow the instructions and get needful investigation and treatment done. Good luck.
Hope it helps you. Wish you a good health.
Anything to ask ? do not hesitate. Thank you.