That is not a keloid. It is a granuloma caused due to chronic inflammatory process(maybe immune reaction to impurities of the metal ear stud).
Next Steps
Meet a good dermatologist to treat it. Once completely healed, meet an ENT Specialist to repierce your ear lobe using a widebore BD needle and fit you with a gold or silver or platinum ear stud as you choose. AVOID COSTUME JEWELLERY as your skin seems to be sensitive to those alloys.