Q. I recently used a home teeth whitening kit that apparently is dental grade. I trimmed back the teeth trays to the gum line as recommended but after using it only 3 times (for a third of the recommended time), I was horrified to find my gums have receeded completely and noticable back, as though they have been burnt off. It does not hurt. Is this normal?! Will they grow back? Should I ever use the product again? Please help! I am very worried about this. Thank you very much.