I get it, I was afraid to get too crazy digging around for the same reasons. Can you post a pic of her foot? If there's swelling and it feels hard you might try surgery now. Or get the PRID and change it every couple of days. It's not expensive and you can buy it at walmart. It will soften the scab and skin of her foot and after a few days you can reevaluate and try again.
I'll be honest, I bought disposable biopsy punches and scalpels. The punch is like a round scalpel that will go straight into the skin and isolate the plug, then you grab it with tweezers and pull it out a bit then cut it off. It's so much easier than digging around in the foot.
If she's fighting an infection then she could be susceptible to getting sick so her breathing would concern me too. The only thing I know of that's OTC and might help is grapefruit seed extract. It's a broad spectrum anti everything that you can buy in liquid form and put in her water. I used about 40 drops in a gallon of water for 10 to 14 days changing every day. Also give plain water. It's no guarantee of course but if you can't take her to a vet it might help while you're treating the bumble foot too.
It's important to get a topical antibiotic that treats staph. I bought Silvex gel, at walmart, and my roo is still in treatment but much better than he was and walks normally.
Good luck with your girl there. I have work but I'll check in later. Have a good day!