I am really worried about my red cap white oranda. He got like a "buble" or a "tumor" on his bottom lip, and it looks like a small balloon which makes his face looks deformed and he cant swim right (Is it a cotton mouth?). The "buble" is his own skin, its like if someone stab you with an air pump and your skin expand. Then, I noticed his skin/scales looks messed up like someone scratched it. His skin supposed to be white, but then I noticed there are some "grayish" spots on his skin. Its very hard to describe and if any of you can tell me what it is please let me know, perhaps some pics (I dont have a digital camera). PLEASE HELP, I am a newb when it comes to fish diseases!!!

Please....
PS:
- The aquarium is 55gl and there are 4 small goldfishes including this one.
- I bought them last Sunday and he was fine until I noticed it this afternoon, last night he was "ok" but he stayed down in the bottom.
- I put him in a quarantine tank, but is the other 3 going to be fine?
- I changed 25% of my 55gl this afternoon.
PLEASE HELP....please....
Thanks for your time guys!