I had to work today so, unfortunately wasn't online when you posted your question about Violet. I'm glad to hear that she was doing so well but sorry to hear about this new problem.
I do see another question which you posted about her which I assume addresses your concern (the oral lesion and now smell which has been detected). I also see that you posted multiple questions about this problem and have asked the moderator to close them so that you don't get charged multiple times for the same question. You might want to double check with customer service that this has been done.
Rodent ulcers don't typically smell, not in my experience anyway, but if you have a highly developed sense of smell, then you might detect an odor. So I have to wonder if there's more going on with her tongue or in her mouth if she's drooling, not eating and there's a noticeable/detectable odor.
I'd want to try and perform as thorough an oral exam as possible to try and better determine what the problem might be. I wouldn't want to sedate her (given her age), but a second opinion might not be a bad idea at all.
A strong oral odor and/or drooling typically means either
1. infection of some sort which would require systemic antibiotics before improvement is seen or
2. a mass which is usually cancer although it gives me no pleasure to say so or
3. significant periodontal disease although this wouldn't develop suddenly
4. possibly uremia which develops secondary to kidney disease
I'd be reluctant to give her steroids at this point since to do so (if this is infection), the problem may worsen.
If the drooling and inappetance issues are somehow related to nausea (commonly seen in cats with kidney issues) and has nothing to do with the oral lesion, then she may benefit from over the counter Pepcid AC at a dose of 1/4th of a 10 mg tablet twice a day.
This drug should be used with caution in cats who suffer from kidney or liver issues but this is at the lower end of the dosage range and should be fine.
I wouldn't advise any other over the counter medication at this time until or unless there's a clearer understanding of what's going on. But, I suspect if the underlying cause of her drooling/mucous production is determined and addressed, then her appetite will return.
I hope this helps and that you'll keep me posted about her. My apologies, again, for the delayed reply. Deb