What Causes Skin Rash?

I wake up and sometimes have a scratch/deep gouge on my face that I have made from my fingernails. I have done it probably about 6-10 times in the last few years. It ends up with a scab and sometimes a slight scar. It sometimes wakes me up. It is always in the same region of my face, right between my left eye and hairline area. Any thoughts as to why I might be doing this? I am a 28 year old female.