Seems like a week is an awful long time for a reaction to set in? What did
they do for it last time? I hope it gets better soon.

Karen

Sounds like rodent ulcer.
________
See my cats:  http://community.webshots.com/album/56955940rWhxAe
Raw Diet Info: http://www.holisticat.com/drjletter.html
http://www.geocities.com/rawfeeders/ForCatsOnly.html
Declawing Info: http://www.wholecat.com/articles/claws.htm

THE EOSINOPHILIC GRANULOMA (also called the linear granulom)

The eosinophilic granuloma produces a classical swollen lower lip or
chin or a classical long, narrow lesion running down the back of the
thigh.

Here's a link to a picture - see the one with the black & white cat.
Ours gets a slightly swollen lower lip.  Causes are not known, but may
be allergy (might be to fleas).  We have found it responds to 500mg
L-Lysine added to his food (L-Lysine is used to alleviate Herpes).
The chin under the lip might seems a little soft/swollen under the
fur.  Certainly check for sores on the backs of the rear legs.

http://www.marvistavet.com/html/eosinophilic_granuloma.html

I had a cat that developed an eosinophilic granuloma that first appeared
as a swelling on it's lip, then developed an ulcer.  Treatment was with
steroids.  The cat went through a siege of them one winter then had no
more trouble.