Red inflammed gums, bad breath...11 months old!! :(

I have two kittens, one is 8 months the other 11 months now.
Both have been tested (twice) for FIV/FeLV and are negative on both counts. Up to date on all shots and live in a clean and spoiled environment, I'm admittedly a bit obsessive in that department.

I have noticed for the past month or so that the 11 month old female has red and inflamed gum line around all teeth in her mouth. I noticed after getting a wiff of bad breath which was unusual to me for a cat, let alone an 11 month old. I can tell it's at least a bit painful when I try to open her mouth as she's very resistant.

I took her to the vet last week, and that's when she had her second FIV/FeLV test just to be sure, along with full blood work to eliminate any other underlying health issues and was told all was perfect in that respect. Also upon a visual inspection, no ulcers in the mouth, or signs of FORLS or stomatitis at this time. The vet suggested it COULD still be a result of teething, but that would be somewhat unusual as she is 11 months and the aftermath of teething should likely have passed.

Since that appointment I have been monitoring as instructed. Although her appetite and energy levels are exactly as normal, I noticed the other day that she seems to be in a bit of pain when chewing her food. I should mention they are both on a combination of freeze dried raw food along with a novel protein wet food rotation due to the 8 month old's allergies (he is prone to eosinophilic regions). But again, this is the female 11 month old with the gum problems.

Thoughts / comments / similar experiences / differential diagnosis?

Other considerations...

-I don't see any visible tartar, but again, as a young kitten I would assume that wouldn't be built up too much yet
-No eye buildup, no coughing, no lethargy
-Coat is has a nice healthy shine
-No behavioural changes

My kitty had bad teeth due to flawed bone structure. Her breath was bad, too. We were given a dental rinse which we had to spread over her teeth daily with a Q-tip. Initially it did not work because there was too much bacteria, so we wound up giving a round of antibiotics and then maintaining with the dental rinse. The vet said it could flare up from time to time, in which case we'd have to use antibiotics again, but it never happened again. The time we did antibiotics I could see a touch of red, inflammed gums.

Thanks for the response! Yes, I guess upon googling her gums aren't an angry red. They are just a darker pink / light red and visibly a bit inflamed, not flush with her teeth. I'm planning to give it another half week or so and then back to the vet. Likely antibiotics is an appropriate next step...

All of my cats have a dark pink gum line and healthy pink gums. I think things that can irritate the gums include excessive chewing, like from grooming. Bad breath can come from bad teeth, parasites, and food. Another possibility for both mouth pain and odor is a blocked gland in the mouth or neck. Salivary glands can get blocked and there are other glands around a cat's mouth that can get blocked or irritated. Gently feel along the jaw line and cheek bones to see if there is any swelling. Retained baby teeth will also cause swelling. A warm compress applied to the painful area will help provide relief and may help the problem resolve itself.

Thanks for the response. Checking both the kitties tonight!