Thanks for posting your query.
Please elaborate the symptoms and the description in detail so that I can help you in a better way by writing about the differentials which can cause the symptoms.
Mention about the site, appearance, color, size, shape, associated symptoms like pain, itching, discharge etc if you have any.
It can be due to whiteheads or folliculitis skin. Folliculitis starts when hair follicles are damaged by friction from clothing or blockage of the follicle. In most cases of folliculitis, the damaged follicles are then infected with the bacteria Staphylococcus (staph).
Hope that this information helps and hope that you will get better soon.
Wishing you good health.
There is no swelling or itchiness and the skin underneath seems normal