I Have Had An Itchy Head For A Few Weeks

I have had an itchy head for a few weeks coupled with a hot spot that has secreted a watery substance... Having shaved my head to see what is going on I have found a large area of scalp that is raised and very red. Skin is creating large quantities of dandruff. I have a similar problem behind one ear with skin flaking and a red area where the skin flakes off.