It sounds like a hematoma. Is it sort of like a pillow on the inside of his ear flap? If so that is what it is. It happens when they shake their head and pop a blood vessel in the ear flap and it then fills up with blood in between the layers of skin. He will need to see a vet for two reasons:
1.) To have the hematomas lanced, drained and sutured back.
2.) To find the cause of why he is shaking his head so- It may be an ear infection or ear mites.
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