Hallow Dear,
In spite of your confidence of having
safe sex, I would suspect your lesion to be Bartholin's
abscess.
Bartholin's glands are situated under
Labia majora. When infected, subsequently they form abscess. Bartholin's abscess in mainly due to sexually transmitted infections like Chlamydia or
Gonorrhoea. The other possibility of
hair root infection also should be considered. You have a well formed abscess.
Once the abscess in formed, it needs incision with marsupialization of the edges to prevent recurrence. Along with appropriate antibiotics to treat the infection is needed.
This being sexually transmitted infection, your sexual partner also should be subjected to medical examination and treatment.
Till both you are declared completely cured, please observe complete sexual abstinence.
Please report to your Gynaecologist ASAP.
Dr. Nishikant Shrotri