With cartilage piercing, the blunt force of an ear piercing instrument will traumatize the cartilage, and therefore make healing more difficult. Also, because there is substantially less blood flow in ear cartilage than in the earlobe, infection is a much more serious issue. There have been several documented cases of severe infections of the upper ear following piercing with an ear piercing instrument, which required courses of antibiotics to clear up. There are many ways that an infection can occur: the most common way is when the person that got pierced decides to take out the piercing too early. According to the A.M.A, the proper waiting period to change or take out a piercing with substantially less risk of infection would be three weeks.