I deal with a lot of abscesses, as I run a sanctuary for guinea pigs with ongoing health issues. Draining an abscess by inserting a needle is incredibly risky. A few years ago, a guinea pig came into our care, where the previous vet had used this method. This had caused the abscess to leak under the skin and form lots more pockets of pus, that had spread throughout the whole of the guinea pigs body. Abscesses must be dealt with properly. Ideally, the whole abscess capsule should be removed. However, this is often not possible, so marsupialisation of the abscess must be carried out. This involves opening the abscess capsule, draining it and then stitching the capsule to the skin, leaving a hole open, to enable flushing of the abscess a number of times a day. The abscess will continue to form pus, as it heals from the inside, outwards. A strong antibiotic will be needed, ideally azithromycin. If this affects appetite, then it is important to step in with syringe feeding. We have also had very good results using a combination of the antibiotics Metronidazole and Marbocyl. It is important to keep the abscess open, and this will involve pulling off any scab that forms, as it must not heal with infection still inside it. It can take 4 to 6 weeks to get a resolution, and it will need constant dedication to flushing and ensuring the hole does not close.