Ive had for over a month two large pimple sized dots on neck and under arm very dry n sometimes intchy?

i have a few also on my scalp and not sure if it the same thing but manly one under my arm is this a sign of a disease or something|||Drink 8 glasses of water per day. You have dry skin.|||You may have a staph infection. Skin staph can show up as pimples. See a Dr.