Colgate Max White Mouthwash Was Expired and Caused Gum Pain

I purchased Colgate Max White mouthwash from an A101 supermarket. I did not specifically check the expiration date when I bought the product, and I later realized that I had used an expired product several times. After using it approximately three or four times, I experienced pain and redness in my gums.

I am concerned that a product that had been expired for so long was still on the store shelves and had not been properly checked. Since I did not keep the receipt, I was unable to return the product to the store, so I am not seeking a refund or making any specific financial demand. However, I would like both Colgate and the retailers that sell its products to pay closer attention to expiration-date checks and conduct the necessary inspections to prevent other consumers from experiencing similar situations.