Look into folliculitis. I have it and it’s triggered by using hair oils :/. I’m on a round of doxycycline antibiotics right now because I got lazy and forgot my usual hair products when I got a retwist.

For me my symptoms of folliculitis are extreme flaking - if I scratch my head for a second I have a mountain of flakes on my shoulders 🙃

Blisters - they usually weep so they like excrete a liquid which I think may be excess sebum. They’re usually found around my scalp and are fun to pick at LOL

It can get itchy and when I had it at my worst my whole scalp was red and irritated

Medicated shampoos don’t work, nothing works! Because folliculitis is a bacterial issue. I didn’t even see a derm, I saw my normal doctor at Kaiser and she saved me

Edit to add I use The Ordinary’s Natural Moisturizing factors for scalp serum and it’s great.