Most likely an aural hematoma (blood filled pocket). Allergic reaction would be another potential cause. Does warrant seeing your vet.

There is a common condition called aural hematoma. It is caused by otitis (irritated ear from allergies and likely a secondary infection, but there are other causes too). The dog experiences scratching and head shaking excessively to the point that the two pieces of cartilage that make up the pinnae (floppy part of the ear) separate and a blood clot forms between the two.

I'd suggest a visit to your primary dvm. Depending on the
size, if left untreated, these will eventually heal but the pinnae may contract as it scars and it can become visually deformed.

***Note this is info only, as I haven't examined your pet.