I cannot confirm anything without examination but it can be due to cherry angiomas,folliculitis,contact dermatitis,sweat dermatitis,heat rash or dermatitis. Cherry angiomas are made up of clusters of tiny capillaries at the surface of the skin, forming a small round dome ("papule"), which may be flat topped.
When they first develop, they may be only a tenth of a millimeter in diameter and almost flat, appearing as small red dots.Pls don’t worry as they are harmless.
Wash the areas several times with fresh water. Do not use any cosmetic products at the sites. You can apply some calamine lotion or Neosporin cream on the spots as it will help in soothing the skin. You can take some OTC oral antihistamine medications like Benadryl or Claritin if the bumps itch.
If still the symptoms do not improve then pls get a clinical examination done by a dermatologist.
Hope it helps.Take care and pls do keep me posted on how you are doing and if you have any additional queries.
thank you. maybe it is cherry angiomas. cause it started out as flat dots and then it became a bump. it's a relief to know that it's harmless. thank you. :D