Welcome to Health care magic.
1.Your history suggest most possible cause could be infective aetiology with collection within probably hair follicular infection.
2.In this case treatment will be a course of antibiotics - that will help.
3.Before that if you are my patient, i would have examine and ask for a
ultrasound scan neck, that will assess the nature of the lesion and its source and extensions.
4.The lump anteriorly with out pain could be
lymph nodal enlargement - seen after localised or systemic infection.
5.I case of large collection a small
incision and drainage followed by the antibiotic is treatment of choice.
6.Do not press, scratch or touch - it will daly healing, clean with antiseptic fluid, avoid clothes that cause irritation to that area. good luck.
Hope it helps you. Wish you a good health.
Anything to ask ? do not hesitate. Thank you.