You don't drain rabbit abscesses. They are not a pocket of fluid pus the way dog/cat abscesses are. They are hard chunks of infection, much like bumble foot in chickens, that need to be debrided in a similar fashion. Debridment is extremely painful and the stress of doing it without anesthesia could potentially kill her. I have seen rabbits die from stress after far less painful (and stressful) procedures. Even if she survives the debridement, the pain afterwords could push her into GI stasis, which could kill her. Bunnies don't do well with pain and there's not a whole lot of pain management options available to them.
If she is a pet, then she really needs to see a vet. Even if you do manage to successfully debride the abscess this time, without proper antibiotics it will simply be back with a vengeance in a matter of days or weeks. I wish I could tell you what those proper antibiotics were, but unfortunately the extent of my knowledge on rabbits and antibiotics is that amoxicillin will kill them and therefor I would be leery of using any related drug (like penicillin) without a rabbit-knowledgeable veterinarians prescription. Even with antibiotics, abscesses can still come back. If she is not a pet, or not quite a pet, and taking her to the vet is prohibitively expensive, then you really need to consider how unfair this is to her and think about culling.
