A bunch of small acne on the cat’s ears may be caused by bacterial folliculitis or parasitic infection. You need to take the cat to the pet hospital for examination to confirm the cause and then carry out targeted treatment. Avoid worsening of the condition. You should pay attention to your cat's hygiene at ordinary times and perform external deworming on your cat once a month. Especially around summer, there will be more parasites, so try not to let your cat go out.