This is probably a minor infection that you could try treating at home unless the piercing is through cartilage. Cartilage is the hard tissue in the rim of the ear. Seek medical care for a cartilage piercing that is painful, itchy, swollen, and very red or dark. Color changes may be easier or harder to see depending on your skin color.
For minor piercing infections in soft tissue, take these steps:
See your healthcare professional if the skin color changes and swelling don't get better or the site oozes blood or pus. Pus can be white, green or yellow.