I have some kind of rash that has started on my hand that is now spread to my face, arm, foot and not trying to sound gross but butt hole and in my mouth also. It itches like crazy and looks like little bubbles or pores filled with water. what could it be?
It is clear case of some kind of allergy and infection following some material attack, food or Chat Doctor.  But filled with water is more suggestive of infective vesicles lime. You haven't mentioned changes in temperature, days taken to spread and any blood work out. Better to meet a doctor near you for physical examination and blood work. Hope it helps you.