That is pretty terrible. I would go to your nearest farm supply store and go to the refrigerated antibiotics and whatnot, get some liquid penicillin immediately! Giving shots suck but i think it's your chance. In the water might have worked had it not been so bad, but that it's still hot isn't a good sign at all. Should cool down pretty quick.
Tylan is good for respiratory issues and a few others but penicillin is good for wounds and staph. (bumblefoot is caused by staph) There are other infections similar that could be an issue.
X2. Make sure you get the right size needles, get Luer lock syringes and shake the penicillin vigorously before drawing it up in the syringe. Let the syringe warm up a few minutes at room temperature before injecting pen. Give 1/2 cc subcutaneous or in the breast muscle, 1/4 cc for Bantam. Here's some helpful info and needle size and treatment with penicillin: https://sites.google.com/a/poultryp...oultry-podiatry#chickens_penicillin_injection