How long does cartilage swelling take to go back to normal if there was some impact to an ear that caused a little bump?

Yes it is possible to shorten the length of ears that may seem too tall in vertical height.  This can be done surgically by removing a wedge of skin and cartilage.  Make sure you consult with an experienced and board certified facial plastic surgeon or plastic surgeon to discuss your concerns.  

I am a UK based plastic surgeon. I have carried out otoplasty by various techniques for many years and I also offer 'Earfold'.Earfold is not for everyone and is not as adaptable as otoplasty. However, it is a relatively simple, quickly performed (minimal surgery compared with otoplasty) ...

There are many ways to perform a procedure but essentially the techniques of otoplasty have been tried and proven over many years. They require multiple point of anchorage, repositioning of cartilage and removal of skin. Ultimately, an ear piercing may exert some effect but unless you want 8...