hi Jessica and welcome....are you feeding dry food? when you mentioned Fromm and Iams you must be, doesn't matter the brand....they have mostly the same ingredients when it comes to preservatives and other additives....I would strongly suggest you try some canned food, any kind your cat will eat...but try to stay away from chicken and fish (I know this is very hard since its so common)
also try a GRAIN FREE type, many cats are highly allergic to grains
I think what you MAY BE dealing with is eosinophilic granuloma...is that the term the Vet mentioned? that can give red raised ulcerated type sores just abt anywhere on the cat, but very common on the face or lips
I will send you a site...scroll down and look at the photo of the kitty with eosin. granul. ...don't be scared this is a very advanced case
http://www.cat-health-guide.org/cat-allergy-symptoms.html
my own cat Sami had a form of this too and after lots of elimination it turned out to possibly be a chicken allergy, also he's intolerant of all dry foods...reacts to one or more of the ingredients. his EOG showed up on his face, sores above the eyes...I have one photo of this I will include, if you believe this is what your kitty has(I do) than change in diet as I mentioned above will clear this up...it will just take awhile, so bare with us...I will help all I can
this is Sami's sore
http://www.medhelp.org/user_photos/show/274134?personal_page_id=473886