Meanwhile, raise the temperature of your frog's enclsure to 30 degree Celcius. Chytrid grows best between 17-24 degree C, and their growth ceases around 29 and will start dying above 30 degree Celcius. In a lab experiment, constant temperature of 30 degree C for 8 straight days can kill chytrid. Not saying you should do that because it's too hot for your frog for too long, but raising the temperature will definitely stunt chytrid growth while you seek solution to saving your frog.