I've been using Sensodyne whitening for about 3 weeks now. The second day of use I developed pain and bleeding of the gum line on one of my incisors. I chalked it up to my very minor gingivitis. A week later and a new spot of pain and bleeding on a different tooth after the first issue had just been resolved lead me to wonder if it was a side effect. During this time I noticed the tip of my tongue was tingly for a hour or so after brushing. I chalked this up to the belief that is how Sensodyne "protected" the nerves (by numbing them).
Earlier today my tongue began to hurt and tingle and I was tasting blood. As I inspected my tongue I noticed that there were tiny sores on the tip of my tongue. I am now convinced that I'm having side effects using Sensodyne and will no longer use this product.