OMG! I am so sorry you are using your last appliance. You better order something on Amazon ASAP. I know you should not pay for your supplies, but this sounds like an emergency! Maybe you could go to ER to get supplies from them?
You should start emailing your medical team (drs nurses) and tell them you are on your last appliance. If they don’t respond, leave multiple messages, be very persistent, and make them understand that this is extremely urgent. They may give you some supplies. I did this, and they gave me a lot of supplies for free.
You need to request a change in your prescription from who wrote it for you at the first place to increase the number of appliances you can get per month. They need to write a letter of necessity to the insurance. If they are not willing to increase it, then you could see a dermatologist and get them to write a letter to the nurses/drs who can increase your prescription, in order to pressure them into writing a letter of necessity to the insurance. They would not dispute a dermatologist’s diagnosis.
I read on one of the forums here on j-pouch.org that ilex paste works for stopping the burning, and can be used under the wafer. I ordered it, but it is not delivered yet. I will update you as soon as I find out. It is available on CVS.
I found that cutting the wafer with almost no gap around the stoma (against nurses advice to leave a gap) works better for me. If I leave a 1/8 gap as advised, the effluent gets to the 1/8 gap, and it immediately starts burning. I put the ring over the wafer, perfectly aligned with the cut. Since the cut is almost the same shape as the stoma, the ring also sits right around the stoma. I tired a million things since surgery, and this works the best for me. Cutting a hole exactly the same shape as the stoma is not easy, but does worth the effort for me. I hope this helps.