guinea pig bump

Question
QUESTION: Hi.  My guinea pig had a nickel size swollen bump for a couple months.  I could push on it a little, it was not hard, and didn't seem to bother him.  I assumed it was maybe fatty tissue.  I just pushed on it the other day and it seemed the inside wanted to come out so I squeezed it and a gross white/gray paste started coming out.  It smells real bad and there's a hole now where I sqeezed all of this out.  He didn't seem to mind until I got to the end and close to his skin. Now he's a little sensitive to me touching the area. I bathed him and really cleaned it out good, but I'm not sure if it's an infection or an insect of some sort.  I had asked you about mites before and you recommended the horse wormer, so I gave him a dose of that also.  He's healthy and furry other than this wound, which is near his hind quarter area.  I poured some peroxide on it and rubbing alcohol with a cotton ball, and it seems to be oozing and foaming.  Should I do anything else?  My vet is not very experienced with guinea  pigs and he put 2 of my last ones on antibiotics when they had "infections" and they both died, so I hesitate to ask them.  Thank you in advance for your help.

ANSWER: Hi Sherri

I can understand your hesitation in going to the vet after your experiences, perhaps he prescribed a penicillin based antibiotic which is poisenous to piggies.

It all depends on whether the lump was fixed to the body or whether it moved when the skin was massaged. If it was fixed it is more likely to be a bigger problem, whereas if not its probably an abcess, hence the puss coming out of it.

You should be ok if you just clean the wound with tee tree oil and keep it clean.

I will be here most of the day if you need further advice.

Andy

P.S I dont remember telling you about horse wormer as ivermectin is the only real treatment for mites but hey ho.

---------- FOLLOW-UP ----------

QUESTION: Thank you Andy.  When you say "if the lump is fixed to the body or moved" what exactly do you mean?  For example, this bump was not rock hard, it was kind of soft to the point where you could press your finger down on it, but you couldn't move it around, like from side to side, it wasn't like a jello substance, it was more a thick paste.  Where can I get tee tree oil, a vitamin store?  Thank you so much.  So should I just assume right now it may heal by keeping it clean and see what happens?  
PS.....yes, Ivermectic is what I have that someone on your website suggested and did help months ago.

Answer
Hi again

What I meant was is the lump attached to the body in such a way that the skin underneath it can't move.

However, I feel sure it is an abcess. Tea tree oil can be bought from vitamin shops I guess but also most supermarkets I should think.

Andy