Hi,
If you can upload me a photograph I will be able to tell you more accurately. Based on your description it might be STD or other infection which your boyfriend might have contracted from you.I would advise you both for a battery of investigation like CBC, CRP, ESR,
liver function test, blood sugar,
VDRL test and urine culture. You both may require a course of antibiotics like Amoxyclav or
Norfloxacin under medical supervision.
I will be able to tell you more precisely if you can write back to me with a photograph and relevant information like your age, how does it appears like vesicles filled with water or pus or red inflammatory area.
Meanwhile use condom during sex and maintain good hygiene, wash your private parts with antiseptic soap or solution and keep it clean and moisturised. Antibiotic ointment like
Mupirocin or
Soframycin can be used for local application.
Hope this answers your question please feel free to ask for follow up question. I will gladly answer you.
Best wishes,
Dr. B R Hudda