Is it normal to have foam after the cotton sheet of salicylic acid is opened?

It's normal! There is no alcohol in their cotton sheets. Generally, because salicylic acid is insoluble in water, many products will use alcohol as a solvent to make salicylic acid soluble in alcohol, which is low in cost, but alcohol will bring a burden to the skin. Therefore, Shi Yan directly removed alcohol and specially developed patented technology to attach salicylic acid essence to high-quality cotton sheets, so there will be a small amount of foam, which is normal and can be used with confidence!