Caitlin, I made a longer post but basically go get head and shoulders clinical strength shampoo and put it on your body where you have this dry, wait around 10 minutes then take a shower, also use it on your head.  Do this 3-4 times over the next 3-4 days and you can even do it twice a day.  Then use it in the shower but you dont have to put it on dry before hand.

Second, get some sun, either tan outside for a what would equal around an hour a day or go to a tanning bed 1-2 times a day.  

How long you have to do this just depends.  I had to do it for around 3-4 days before I had a very large and noticeable improvement.  Itching was gone after day 3-4 and it's pretty much all gone now about a week after doing this.