Absolutely! That's what it looks like to me. You may not have completely cleaned out the infection when you treated her last time.
You are going to have to open that up and clean the pus out or you're going to lose her eventually. Meanwhile, it's going to be painful and make her sick.
Try not to be squeamish. You need to do this for her. She'll be a very good patient, I promise you. I can tell you exactly how to do it, and you will be able to take your time and do a good job.
You will need to get hold of some antibiotics and start her on them right away. The infection has probably got a real hold in her system.
What you will do is to get the supplies together you'll need. A sharp pen knife or Exacto-knife or even a razor blade will do. You'll need two tubs of warm epsom salt water Some vet wrap - cut a piece an inch wide and a foot long, bandaids, Vetericyn, and antibiotic ointment. It would help to have some Betadine or generic 10% iodine solution.
When you have the supplies together, the first thing to do is soak her feet in the warm epsom salt water for fifteen minutes. If you settle her in, drape a towel over her back and head so she can't see anything, she's likely to calmly stand there in the water indefinitely. Make it a small basin, though, so she won't drown if she falls asleep.
Next, dry her feet, and wrap her tightly in a towel so she has her head covered and wings are immobilized. Then lay her on her side on a well-lighted operating table. She will be calm and won't move or fuss.
If you have the Betadine or iodine, dip the razor blade in it and coat her foot with it with a Q-tip. Make a one-quarter inch shallow cut across the middle of the swollen area. If you don't hit pus, make the cut a little deeper until pus squirts out. Squeeze out as much pus and any black tissue. If you encounter surrounding tissue that is blackened, you will need to cut it away. Any black tissue left behind will just keep the infection going.
After you've cleaned out the cavity as best you can, return her to the second tub of warm epsom salt for five minutes. Take her out and see if any more diseased tissue can be seen and remove any you see.
Dry her foot well and pack the foot with antibiotic ointment. I like to spray first with Vetericyn spray, then put on the ointment. Place a non-stick bandaid over the ointment, then wrap the foot, not too tightly, with vet wrap. I start at the wound, go around the foot and between each toe, and end up around her shank so the bandage is more likely to stay in place. I let my patients go back to the run with the other chickens because the bandage keeps all dirt from getting in the wound, and they're happier back with the flock. Just check her often to make sure the bandage is still on. If it should come off, soak in epsom salts and re-do the spray and ointment and re-bandage.
Leave the bandage on for three days, and then remove it and check her wound. You may need to soak it again in epsom salt. Repeat the Vetericyn spray and antibiotic ointment and bandage it up again like you did before.
I would check it and repeat this procedure every two or three days until the wound closes and you see healing. The swelling should be decreasing by this time. When you see it's closed up, leave the bandage off and continue to spray with Vetericyn twice a day. She should be on antibiotics for a full ten days.
The hardest part is the cut. After that, it will go smoothly, and I promise you that your patient will not give you any hassle at all.