First, welcome to the Forum. Unfortunately, I am one of the few people that do not own one of these amazing frogs, so in terms of care or first aid for them, I will not be of much help. However, pictures do speak a thousand words and if there is any way you could take some pictures of the nose rub and the blisters, I am sure will be able to help you better.
However, on one note, it sounds like you are housing these two species together. I realize that they come from Australia, but they really should be housed apart. Both these species will get large, especially the White-Lipped, which may also need more specific care (such as temperatures and humidity) than the White's treefrog. I could also be wrong on this, but White-Lipped treefrogs, from what information I have read, are still mostly wild-caught. Wild-caught means natural parasites which have now been introduced to your captive bred White's.
We do have a First Aid thread located to the left. I am not sure if it has any information on possible burns, but it does have some very useful information. Best of luck and I hope we can help you.