Scalp pimples... What shampoo would be good?

My skin condition is generally a mess these days, perhaps because I'm tired. I started seeing slight signs of dermatitis on my face, and now my scalp is giving me trouble too, with pimples popping up one by one. It bothers me because I catch them on my fingertips every time I wash my hair, and it stings a bit, so it's really stressing me out.

I'm not sure if the shampoo I usually use is too strong for cleansing, or if it's because I haven't been feeling well lately. In times like this, would it be a good idea to switch to a gentle, slightly acidic shampoo or a product with soothing ingredients? If you happen to have any products that worked well for a sensitive scalp, please recommend them.