What to do if ears pierced for years and now swollen earlobe?

Infection: If the ear lobe is red and tender in addition to being swollen, then you have an infection. Treatment is either hot soaks or incision and drainage.

Infection vs cyst: Even pierced years ago, ears may develop infection. There may also have developed a small cyst that either IS the swelling or predisposes to infection. It was be appropriate to have this evaluated by medical professional.