Hello,
Without examination,confirmation of a diagnosis is tough but it can be contact dermatitis,rash due to friction rub,folliculitis,cysts or sebaceous glands.
Apply warm compresses,Neosporin ointment and calamine lotion and avoid messing with it.You 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.
I hope that helps.Take care and pls do keep me posted on how you are doing or if you have any additional doubts.Kind regards.
Mostly sebaceous glands which are visible.