There are many causes for such a lump and these include a cyst, HPV wart or some benign or malignant growth like a dysplastic growth. You need to get a pelvic examination, a PAP smear and biopsy of the lump done to confirm the diagnosis.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
This sounds like and infected hair follicle and its common in the genital area. If you squeeze it and pus comes out then that's what it most likely is. See a dermatologist however if you want piece of mind.