Tumor burst?

Question
My guinea pig developed a lump at his rump. Eventually it grew into a golf ball. Last night, it burst. But there was no blood. Just something of a clay or dirt substance is inside. It has an odor to it as well. It seems as if this whole golf size lump is filled with this substance. It doesn't seem to effect him, but only bother him as if it is irritating. He doesn't seem hurt or isn't acting different. He eats, drinks, and talks as if nothing happened. And before, he never let me touch his bump, now he lets me touch and examine it. I have a vet appointment next week, but I'm scared that this isn't going to be soon enough? What do you think it is? And should I attempt to look for a vet that can take me sooner? Please help.

Answer
Hi Ginger!

Well, what your guinea pig has is either an abscess or a cyst.  An abscess is an infection and needs treatment.  A cyst is not and needs maybe occational draining, but no other treatment.  Cysts are not painful, so I don't think that you're dealing with a cyst.  Abscesses are sore until they burst, which relives the pain.  An abscess should be treated immediately.  You can do this at home with some concerted effort unless the infection has become systemic (moved into the bloodstream).  Also, cysts do not have a bad odor, but abscesses do.

Drain the pus from the abscess, clean it with an antibacterial soap, rinse and then fill the hole with triple antibiotic ointment.  Continue this treatment until the area heals, but don't let the hole close up so that it can not drain!  If you believe that the infection may have moved into the bloodstream or just want to be extra sure, see the vet as soon as you can.  Don't wait until next week.  Make sure the vet doesn't prescribe any penicillin family antibiotics, they are toxic to guinea pigs.  Baytril is a safe alternative.

I hope this helps.  Your piggie should be fine with proper treatment.

Annie