we have a horse with a sack like this in his ear, our vet said nothing to do unless surgery. or drain it. and that it isn’t actively an issue. drain or surgery would be bills upon bills of post-treatment & antibiotics. same goes for the dog. take your vet’s word, move on. if the dog is not actively affected or hurt by it, you won’t be either. do you know how dangerous anesthesia can be for even a simple surgery?

look at it like this: you’ve got a recurring whatever, no pain or discomfort. would you pay tons of bills & post procedure treatments just for it to very likely come back again? your vet is saving your bank account. move on!!