Hi,
Response:
I purposely keep my hair short to avoid using surfactant agents. I can definitely think of a few products that irritate my psoriasis. So, just be aware that you might just have sensitive skin and using something irritating on top of already inflamed skin will do exactly as you describe--worsen it. Go for several days just using lukewarm water to wash your face and scalp. You might be surprised at how well your skin responds. Just also be aware that hard water can "de-fat" your skin just like alcohol can. Certainly, most cleaning agents have components that strip your skin barrier leading to irritation and inflammation.

Response:
I have combination skin as well--so much fun to get pimples and P at the same time--it's hard to figure out what to do!
I use Aveda's "sensitive skin' facial cleanser and am very gentle with washing, but am thorough as to clean out the pores. Then I use the Aveda "sensitive skin" toner that tightens up the pores. (this helps with the acne). I never exfoliate since that makes the P worse. Then I use a facial moisturizer for sensitive skin (apply liberally), with lavender as one of the ingredients. It helps reduce the redness from the P and the acne.
So: all sensitive skin products: cleanse, tone and moisturize. It has helped me quite a bit.
I don't have scalp P though, so not sure how that works.
Melanie