The location does give rise to conditions like an ingrown hair or folliculitis
, etc; but it is difficult for me to say so without looking exactly at the region affected.
Although most of your symptoms do not match the typical symptoms of an infection, I would like to ask if you are expriencing a response since you have initiated the medication (usually takes 24-48 hours) to experience an improvement, although minor.
If you are not experiencing an improvement then your doctor will have to relook into the suspected diagnosis.
I would advice a repeat physical examination, a urine analysis and even a vaginal swab test. The lump you have mentioned will have to be looked into with more detail and cause found.
In the meantime, please consume plenty of water and avoid sexual contact in all forms.
Hope this helps. I am sorry I could not be of much assistance as your presentation is vague and it is difficult to comment on it without a physical examination.