Well, it might not be dry scalp at all. Since you said you usually have oily hair I bet you it's exactly the opposite of dry scalp. When the scalp gets a build up of stuff like oil or even hair care products, it will start to flake. Alot of people mistake this for dry scalp when really it's not. A way to tell... Stand over a black or dark piece of paper, tilt your head downward, and start to kind-of scratch and shake your head. When the flakes fall on the black paper take a look at them. If they are fine, small, or grainy looking then it's dry scalp. If the flakes are larger and actually look like flakes (as opposed to the grainy look)then it's probably oil builup. If it turns out being oil buildup there are a couple of things you can try. Go to a salon or beauty products store and look for a balancing shampoo-biolage makes a good balancing shampoo as well as Aveda's "Scalp Benefits" shampoo. Something else I've tried that worked was getting a botle of aloe vera gel at the drugstore(the pure aloe vera with no alchohol)and coat your scalp with it. You can leave it on overnight or for like 30 minutes if your in a hurry. If you do this a couple of nights in a row it will help. I've also heard lemon juice on the scalp works too. Good luck!