Please recommend a good shampoo or routine for seborrheic dermatitis.

Lately, I’ve been so stressed because I’ve been getting pimples on my scalp and a lot of dandruff due to dead skin cells, possibly due to seborrheic dermatitis. I even tried ordering Nizoral or Head & Shoulders Clinical Strength shampoo online, which are said to be effective for seborrheic dermatitis, but I didn't see much effect. Please let me know if you have any shampoos that are good for seborrheic dermatitis, or if you have any personal methods to overcome this, even if it isn't a shampoo.