Should this be a need for concern

My 4 month almost 5 month likes to scratch head to soothe herself. I have noticed once she gets sleepy she will scratch all over her head till she falls asleep and pull the hair a little and once she sleep she does it for another 30 sec or so. Should I be concerned with this or stop this so she not pulling her hair out. And some times she will leave tiny scratch mark on her scalp from scratching her head. I try keep her nails extra short because of this but my goodness her nails grow fast. When I comb her hair they is always scratch’s and tiny dry bleed from all the scratching and pulling she does whenever she sleepy rather it be a nap or bed time. Anyone else have this idk what to do.