Most skin bumps, spots, growths, and moles are harmless. Colored
skin spots, also called pigmented lesions (such as freckles,
moles, or flesh-colored skin spots), or growths (such as warts
or skin tags) may be present at birth or develop as the skin
ages. Most skin spots on babies will go away without treatment
within a few months. Birthmarks are colored marks on the skin
that are present at birth or develop shortly after birth. They
can be many different sizes, shapes, and colors, including
brown, tan, black, blue, pink, white, red, or purple. Some
birthmarks appear on the surface of the skin, some are raised
above the surface of the skin, and some occur under the skin.
Most birthmarks are harmless and do not need treatment. Many
birthmarks change, grow, shrink, or disappear. There are many
types of birthmarks, and some are more common than others. For
more information, see the topic Birthmarks. Cause of skin
changes Acne is a common skin change that occurs during the teen
years and may last into adulthood.