Thank you for the link, that's a useful post. I am going to see if I can convince a friend to come and treat her for me while I am gone.
In addition to the link Heidi65 gave, here's a thread that might help relieve her pain, or carry her through the week until you're back:
https://www.backyardchickens.com/t/915880/bumblefoot-cure
Think about it like having a thorn stuck in the bottom of your heel and cutting a hole in your shoe so the shoe isn't pushing on that spot when you step. Essentially you're building her a little "O" shaped shoe cushion- in your hen's case, to elevate her toe with respect to the rest of her foot. If your friend is willing to treat her and remove the scab, all the better- in case it's not possible, this is at least something to try.
Some have used just the foot cushion and left the scab in place- over time it should get pushed out (others describe their experiences in that thread) and with the pressure off her sore spot, she continues on.
There are a couple ways to go about making one- one suggestion was pipe insulation (the gray foam stuff, probably 1/2", maybe 3/4"??) wrapped in vetwrap that already has the hole in the middle- put vet wrap over the pipe insulation, apply it to the foot, then wrap her foot over the bandage used to protect the site. If it seems like you need more height to the ring, I'd suggest the flatter version of a hose ring (the little plastic O ring that keeps your hose from squirting water everywhere at the faucet or sprayer attachment)-- then put the foam insulation on top of it, then vet wrap the foam insulation and hose ring together... the part with the foam is the part that would face her foot. Specifically, post #1, 3, 8, 18, 22, 27 (most like your situation) are most applicable- since you're short on time.
Aspirin might help her get back on her feet - I think the dose is 25mg per pound of bird per day, but double check me on that. Chewable baby aspirin (81mg) is my favorite because it's already sweet. If she'll eat it whole tucked into a grape or blueberry, or crushed into some plain yogurt or other favorite treat- so long as she eats it all.
Good luck!