I Have A Pimple On My Arm. You can encourage the pimple to come to a head on its own by using a warm compress. A small or pea-sized lump in the armpit can also be caused by a skin infection like a cyst or ingrown hair.
However most keratosis pilaris bumps on the arms are small and flat. The only way to heal these things is to get the pus out. If it is tender andor enlarging then have it checked.
They may grow rapidly or may not change in size.
For example a high-energy blow to the arm can cause not only a superficial bruise but deep tissue swelling. In addition you may need antibiotics. Some of the common causes of upper arm pimple include sweat sebaceous gland friction allergic reaction androgens estrogens. Top 7 Causes of Painful Arm Bumps 1.
