By Trish Rooney First, it wasdry brushing your body. Then, it was “slugging” your skin at night. Now, self-care has come all the way for the top: your scalp. Tik Tok has blown up with trends around hair care, starting at the root (literally). Whether that’s scalp “detoxing” videos of estheticians removing dandruff from scalps, or hair shampooing videos that show full scalp massages, a healthy scalp is the new body trend of the moment to give you your best hair ever. In an interview for NYLON, Lisa Nurczyk, director of education at cosmetology, barber, and esthetics school, Tricoci University o…