A lot of the abscess is often made up of infected and swollen tissues, not just pus. the pus exudes from the tissues and builds up, and then bursts.
Body abscesses are normally easier than facial ones.
I recommend that you try and get saline as deep into it as possible without causing your rat distress. digging into an abscess is also not always a good idea unless you know what you are doing, so sticking things into is a bad idea usually. syringing it with saline solution 2-3 times a day (I have had a rat with abscess and I used to do it every 6 hours) is fine. if you can get saline into it, and the saline runs out freely, then that is okay. you don't want to trap more fluids inside, or have the fluids go where they are not supposed to.
If you think that the abscess needs to be opened up more and some of it needs to be debrided, then seek advice from your vet. I know that when my rat had an abscess the vet debrided it and it healed well but left my rat with a hairless patch on her neck (she got bitten on the side of her neck and it got rather badly infected and formed an abscess). This was maybe 6 years back now, though.
It is important to give pain meds if you think your rat is in pain and it is probably a good idea to give antibiotics to help prevent the spread. remember that the antibiotics will not really work on the abscess very well, but it does help to stop secondary infection and spread.
I think that the ratguide does sum it up well, as mentioned above.
I really do not think that sticking Q-tips into the abscess is a good idea though - you don't really know what is going on inside. If there is an opening and pus drains freely, that is good, and you do not need to poke about inside. you can make it worse by doing so. If it is not draining properly, getting it checked out by your vet is a good idea.
Abscesses are very common in rats when they get bitten and stuff. They tend to handle it quite well with proper treatment and support.