Looks like bumblefoot. A staph infection. That lump of infection will need to be removed. See the link. https://www.backyardchickens.com/t/236649/bumblefoot-surgery-with-pics-and-how-to
That looks like a fungal infection. Neosporin will do NO good. I would soak in Epsom salt and warm water then apply an anti- fungal cream like lotrimin. Good luck
I know that I am spoiled with the horizontal nipples, as long as it's not freezing. (My mistake for not setting it up right to start with) Hauling water is for the birds. Lol
This is my problem too. I have the exact set-up. I found a submersible aquarium heater at Petco. Com but haven't purchased it yet. The idea is to "snake" the heater from the Rubbermaid cooler thru the hose and down to the PVC. It's worth a try so I may just give it a whirl!!!
Ps. The heater...
It sounds like ther is pus in there. It will have to be removed. You will be amazed how quickly it will heal after you remove the pus. Anything else will just prolong her suffering.