Unlike the majority of hair masks on the market, most scalp masks focus less on hair and more on skin, though it's important to remember that the two are inherently related. So naturally, choosing the best scalp mask for you will depend on two things: your skin type, and the hair-related concerns you're dealing with.
For example, if you're prone to dry hair or a dry scalp, choose a deeply nourishing mask that provides plenty of moisture. If you have dandruff that causes itching or flaking, there are medicated scalp treatments with antibacterial ingredients that may be able help ease these symptoms. There are even refreshing scalp masks that remove product buildup, kind of similar to how a clarifying shampoo works.
For the ultimate scalp "facial," precede your scalp mask with a scalp scrub or thorough shampooing session (consider picking up a scalp brush if you're extra fancy). Keep in mind, if you have eczema, psoriasis, or open cuts on your scalp, be sure to check with your doctor before using any new products.