I started using Listerine Whitening Pre-Brush rinse about three days ago. The first time I used it, I felt this slight stinging in my cheek on the right side. I didn't think it was anything to worry about. I used it on a second day and didn't have any symptoms other than peeling gums. The third day, in the morning I used it and was OK. I used it at night and this is when my symptoms suddenly appeared. About two hours after I used the mouthwash, my mouth had this bitter taste. I went to get a glass of water and a small piece of chocolate candy bar (like the size of my thumbnail) just to suck on so the bad taste would go away. As soon as I swallowed the piece of chocolate, the gland on the right side of my neck swelled up a little, very suddenly. You know how when you eat something zesty (like B-BQ sause) you feel that sensation at the sides of your neck? That's how it was with that little piece of chocolate, only much more intense as if I overwhelmed a lymph node or something. I know I'm not allergic to Hershey's b/c I've had it before. So I don't know what else could have sparked this other than the chemicals in the Listerine. I woke up this morning and my neck is still a little swollen, just like last night. AND the weirdest part of all this is that when I eat anything, even the blandest bowl of Cheerios, I get that intensely zesty-swelling sensation in that gland. What can I do to make this swelling and this irritating sensation go away?