My scalp is often itchy and flaky, and it feels like scabs. sometimes there's a little blood when i scratch it. i've tried dandruff shampoos but they haven't worked. i've also tried off-the-shelf treatments but they sting. what can i do?

See a dermatologist: You need a professional diagnosis and probably a prescription. You fail to name anything you tried so far and you fail to indicate how anything was used or how often. Meanwhile you can try T-SAL or ketoconazole or selenium or zinc pyrethrum every day in the shower. Sprinkle some water on it, then rub in a drop of shampoo several hours before the shower.

See dermatologist: In order to find the right treatment, one needs to identify the problem. Aside from a contact allergy to hair preparations, you may have condition such as seborrhea or psoriasis. Thus a dermatology consult would likely be the best option for you.