The other possibility is of a cyst which is formed when irritants like
oil, sweat, dirt, perfume, hairspray
and lots of other things can aggravate a piercing
and cause an infection. It will create a growth filled with blood, puss, and or sebum but it is usually painful and may discharge pus or blood. If it is a keloid that you are having, then surgical excision is to be done. Please get it examined from a dermatologist to confirm the diagnosis.
Hope it helps.