Have you been tested for H. Pylori and SIBO? I've gotten the fart smell as well. I'd lick my lips, and smell fart. I thought maybe I used an expired lip gloss or something, but after cleaning my lips, it was still there....it was my tongue. I tested positive for both of the conditions listed above. I've been on a few rounds of antibiotics, which hasn't helped. In the past, eating only chicken, vegetables, and at least half-gallon of water helped. I think it's something genetic. It might have something to do with MTHFR gene, I've been looking into this. People with this mutation have a problem with b12, I believe. Buttermilk immediately causes a problem; anything with yeast, sulfur, bacteria, or enriched items can cause issues. This is a terrible disease!