How do you take care of your scalp?

I used to get contact dermatitis and seborrheic dermatitis on my face occasionally, and now it's affecting my scalp too. ㅠㅠ I'm getting red, acne-like bumps on my scalp, or inflammation that itches and hurts when I press on it. ㅠㅠ Even using a shampoo specifically for seborrheic scalps only provides temporary relief, so the symptoms keep coming back. ㅠㅠ Please share some tips on how to manage a seborrheic scalp.