What Causes Sensitivity Of Skin In A 20 Year Old?

im 20 year a female
i have skin sensitive
i dont know what is the reason
i have this sensitive since 3 years ago
i peeling my skin when i be sleep
and i didn't feel anything about it until i wake up and i found the blood in all my hand and nail
and also in my clothes
please doctors help me out in this
and tell me what is this caused of this sensitive and how to deal with it.
thanks alot doctors