guinea pig abscess

I found this lump on my guinea pigs ear and panicked would anyone know what it is?

I have two beautiful guinea pigs named Henry and Celestine (both female). Celestine, the younger female piggy, has had struggles with abscesses. She first had an abscess that was lanced and drained and healed but a new one has grown back. The abscess is on her chin/neck area and is quite large...

I have a six year old male gpig Gibby, and a four month old female Alaska. They are in separate cages obviously! :) we got our new little lady last month totally unexpectedly. We went to Petco to get supplies for Gibby and our other pets and stopped to quickly look at the babies they had...