Tiny blisters all over hands. spreading fast. itchy and painful. what could they be?

General thoughts: Without an actual examination, I cannot give specific medical advice on your particular health, Dermatologic conditions are hard to evaluate without seeing them in person. Conditions that are localized often are due to a particular exposure (contact with something causing an allergy). This is particularly true of hands. These are often itchy. Anti-immune medicines (antihistmine/steroids) ...