Had hair bleached blonde today. Now I have blisters on scalp, swollen hands, mad with the itch on hands arms feet and groin area.

See a dermatologist. Indicate that you have an urgent problem. Benadryl (diphenhydramine) will only make you sleepy, not help your skin. You need diagnosis and probably corticosteroid pills + cream. Likely allergic reaction to something used on hair.
Allergy to chemicals. this is probably an allergy to chemicals.take benadryl (diphenhydramine).if it persists you will need to see a dr and possibly need steroids.