Yes, salicylic acid can be used on damp skin. In fact, applying salicylic acid to slightly damp skin can enhance its efficacy. Salicylic acid is a beta-hydroxy acid (BHA) that is oil-soluble, meaning it can penetrate through the lipid layers of the skin. When applied to damp skin, the water present on the skin's surface helps to solubilize the salicylic acid, allowing it to penetrate more effectively. Additionally, damp skin can also help to minimize potential irritation that may occur when using salicylic acid at full strength. Overall, applying salicylic acid to damp skin can optimize its absorption and reduce the risk of irritation. However, it's important to note that everyone's skin is unique, so it's always a good idea to perform a patch test before using any new product.