My Weave Is Dry Im Mixed Raced & Have A Partial Weave. I Have Dry Scalp, And Nothing I Do Will Stop The Itching Plz Help!?

Im mixed raced & have a partial weave. I have dry scalp, and nothing I do will stop the itching plz help!? - my weave is dry

I had the stuff for three weeks and it seems impossible to clean my scalp ... I used to wash my hair every two days, so now my scalp is dry and crusty, while my natural hair is greasy.