When I started kefir, I had bad reactions. A lot of Acne bumps started to break out in my back, and it burned a lot. Each time I drank the kefir, one hour later it started to itch and burned. Then slowly, the sensation disappeard, and now I starting to have better BM. There's no more burning, just a slight itching. I drink raw goat milk kefir in the evening, and water kefir during the day.
Maybe you should try to go on drinking it and see what happens.