I practice a grappling martial art. If you bruise the tissue in your ear too much small pockets of fluid can form between your ear and the cartilage. If this fl

I practice a grappling martial art. If you bruise the tissue in your ear too much small pockets of fluid can form between your ear and the cartilage. If this fluid is not drained and the ear kept compressed it can harden forming cauliflower ear, deforming the ear. Some people are more susceptible to it than others. I imagine that would be a worst case injury. I don’t know of this happening with headphones, but it seems plausible.