I would recommend that you see an ENT (Ears Nose Throat physician). You are correct in saying that the ear is made up of cartilage. Cartilage if the flexible, yet rigid framework that gives the ear its distinctive shape and aids in directing sound waves down the external ear canal for hearing. Cartilage itself has very little blood supply to it. There are no major names blood vessels that supply cartilage with nutrient blood flow. Rather cartilage receives its blood flow from the vascular lining over top of it called perichondrium. It is possible through trauma to develop a collection of blood underneath the perichondrium. This unfortunately separates the perichondrium from the cartilage underneath and cuts off some of the nutrient supply to the cartilage. This can ultimately lead to cartilage death and disfiguring of the cartilage and the ear. This is the process that happens with "cauliflower ear" which is seen relatively commonly in boxing. The treatment is to drain the collection of blood, and put a pressure dressing on that pushes the perichondrium back down to contact the cartilage. See your doctor
soon, and best of luck.