What body part or system do substances applied to your skin enter before moving to other parts of the body?

Substances applied to the skin primarily enter through the epidermis, the outermost layer of skin, before reaching the dermis, which contains blood vessels. From the dermis, these substances can then diffuse into the bloodstream and be transported to other parts of the body. The absorption process is influenced by factors such as the chemical composition of the substance, skin integrity, and the area of application.