Pores are openings on the skin that release sweat and oil to the surface of the skin from the glands that produce it below. They help to keep the skin cool and hydrated and can vary in size. Some have very large, obvious pores that can be reduced with the right skin care.
When pores become blocked (by bacteria, sebum or dirt) it can lead to spots and blemishes. When sweat blocks the pores is can lead to heat rash. Look for products described as non-comedogenic, as these won’t block the pores, reducing the possibility of skin issues developing.