Itchy bumps on head?

Hey everyone so for the past week and 2 days I’ve had a really itchy scalp. It started as my hair getting really oily right after a wash, so i switched my shampoo and conditioner- as sometimes this happens and its just because my hair is too used to it.

I then noticed my head becoming super itchy and like burning almost. So i decided “let’s get itch shampoo, do a tea tree oil treatment and get conditioner for your scalp”

I tried that and it worked for a few hours. A few days later I’m still having this issue, and i noticed where I’m itchy i have like bumps that are barely raised- but still feel-able and not see-able.

Has anyone had this before or know what it could be/ how to treat it? I feel like I’m just making my natural oils messed up by itching and my hair is flat and nasty now! I know it’s not lice as I’ve gone through it with a fine tooth comb and haven’t seen anything!