Hello,
Without examination,confirmation of a diagnosis is tough but it can be contact dermatitis,rash due to friction rub,folliculitis,cysts ,molluscum
depression or plug) or genital warts(caused by HPV infection).They may present as flat warts initially.
Ask your boyfriend to apply warm compresses,Neosporin ointment and calamine lotion and avoid messing with it.He can take anti-inflammatory pain killers like ibuprofen or acetaminophen.If the lumps persists then it will be best to get it evaluated from a dermatologist.
Hope it helps. Take care and pls do keep me posted on how your boyfriend is doing or if you have any additional queries.