After sex a friction burn immediately appeared. 1 week later a few water blisters. Occasional tingling and itching. Lots of sweating. Herpes or not?

Good possibility. Little water blisters that appear in the genitals area or on the face are often herpes (other rashes usually are not little water blisters). A doctor can look at the blisters when they pop up again. There is treatment for genital herpes, but no cure.