hi,thanks for writing here,,Red ,swollen,warm to touch ear cartilage
after piercing is suggestive of chondritis
means inflamation of ear cartilage.You need to take oral antibiotics
like amox clav and anti inflamatory drugs.It is better you consult a doctor near by and start treatment.At home you can just apply ice over affected area to get some relief and you can take tab.combiflam,but better consult a dermatologist
or ent surgeon as early as possible.