I have a bitch who had an ear infection similar to yours. What i end up doing was popped it(poke) it with a needle and squeezed the puss out. That didn't work cause i couldn't get to the main source where it was producing the puss. So i end up using a sharp knife and sliced it deep enough to get into the infection and squeezed out most of the infection. Gave her antibiotics for a week and she recovered. Oh yeah my bitches infection is more in the canal so from the side view the bump is located under her ear.