Swollen lips, blisters on inside of lips, sore tongue, after using for one week. After stopping use, the blister inside my upper lip seems to be spreading some. My lips are swollen. I had a similar lip swelling reaction when I have used plain hydrogen peroxide on a cotton swab to clean a place on my inside jaw where I had bitten it. I didn't get the blisters, but my bottom lips was very swollen. If you have a sensitivity to hydrogen peroxide, I would not use this product. This product also made my whole mouth hurt, my tongue felt generally sore.