Contaminants like nickel, chromium or cobalt in earrings can cause an allergic reaction which may get infected later. Stop using the earrings and clean the area regularly with an anti-septic like Savlon or Betadine solution. Apply an antibiotic cream such as Soframycin or creams containing an antibiotic, anti-fungal and steroid such as Betnovate GM or Nadimix. If the ear lobes do not respond, get a culture sensitivity done. If the infection spreads to the nearby cartilage or further larger area around, you may require oral antibiotics and anti-allergic and anti-inflammatory medications in addition.