Sick yellow tang

[foxface]

My yellow tang has been in QT with cupramine since monday and is doing better in terms of ich, spots are gone, no more scratching, white film on her body and eyes is gone but under a flashlight in the dark I can still see something, maybe scaring or something, it only shows up with a flashlight and it look like tiny specs.
Anyways what is mostly bothering me now is she won't eat, hasn't touched anything in 4 days and for 2 days her mouth wouldn't close!! Today it's almost closed and she looks a little happier.
Also I did a ammonia, nitrate nitrite test and the nitrites were 0.1 on the Seachem test.
Could this be because she is in a 10 gallon tank? I know she's quite big for this tank but that's all I have right now. I went to the LFS and they told me to put in "CYCLE" in a double dose ( I wanted to use prime be he convinced me to use cycle) and I'm doing a 25% water change today but usually it's about 12% every 2 days.
Is there something else wrong with her that I don't see? How can I make her eat?
I hate that I'm putting her through all this horror but I don't want to let her die!!