What Causes Swelling On The Left Side Of The Tongue?

Question: Hello
I have been dealing with something called “burning mouth syndrome” for a while—I’ve seen several professionals for this and am learning to live with it.
Today, however, and perhaps a few times over the past week, I’m noticing that the left side of my tongue seems a bit swollen. I think. This area often aches and is the center of much of the burning sensation. I have been examined by dentist- twice now. There are no visible lesions of any sort. I’m attaching pictures as best I can. I’m not sure how well it will show anything.
I'm ashamed to admit this is making me a bit anxious. Is there any concern for something more nefarious- tongue cancer? No lesions, just an occasional ache and this bit of swelling.

Thank you kindly for your reply.
I have been dealing with burning mouth syndrome for a year now. I have seen several specialists ranging from dentist, ENT to neurologist.
The origin in my case is felt to be very strange. I had a definite immediate reaction to taking a drug called diflucan in Aug/08 for a vaginal yeast infection. First one I ever had- at age 49. Within 48 hours, my tongue and lips started to burn terribly.
I never made the connection—who would. I thought it an allergic reaction perhaps to something I ate. No one could figure it out. I had started to improve somewhat when in November I developed a second yeast infection, again was prescribed the medication and had the same immediate reaction, but worse. This time I made the connection. I’ve seen a neurologist specializing in the condition and he tells me I am the third person he has seen who developed this after taking diflucan. It is rare, but known supposedly. Hypothesis—This strong antifungal upset the balance in the mouth and allowed the (latent) shingles virus to flourish, affecting the trigeminal nerve path to the tongue. Basically- a rashless case of shingles that left herpetic nerve damage in its wake. I’m not really sure I’m on board with this—but not much about this makes sense. No one else has any idea. It's been very frustrating and hard to deal with. I'm seeing a psychologist for help in learning to live with it, but the anxiety gets to me sometimes.
I have pretty severe drug sensitivities and know which ones to avoid. Antidepressants are not an option for me. I had tried at this point Neurontin, which was no help. Also valium, no effect and did not wish to be addicted. Right now, I am trying a very lo dose klonapin swish and spit—but sparingly and it doesn’t really help anyhow. I mostly get through the day with gum and xylimelts, which help the most. I avoid anything citric and very sugary as that has an effect as well.
The burn feels like black pepper on my tongue and will at times spread to my lips and upper palate. What concerns me now it this tendency for the tongue to ache (can this be nerve related as well?) and the swelling I see in the area that aches.

Thank you for your swift reply and looking at the photos