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1.The history suggest the possible cause of the lump in the groin area could be hair follicular infection / inflammation with collection within.
2.Which is an infective aetiology - which needs a small
incision and drainage followed by antibiotics.
3.The second possibile cause could be enlarged
lymph nodes - which is seen after any infection / inflammation, can be localised or systemic.
4.As an investigative tool,
ultrasound examination will be helpful to evaluate the nature of the lump, its source and extensions, presence / absence of blood supply.
5.At this point i would suggest to see your GP, get it examined and request for an ultrasound if required and treated accordingly.
Good luck.
Hope i have answered your query,
any thing to ask ? do not hesitate to ask.
http://doctor.healthcaremagic.com/doctors/dr-ganesh/62888