I had very mild herpes zoster just 8 blisters and I am cured now my pregnancy test is positive now after 5 days of medicine. Can it affect the fetus?

Zoster. It should not affect the fetus. It is a reactivation of the virus that you have had since chicken pox (or the vaccine) in your youth. With shingles (zoster), the virus does not travel through the blood stream - it travels locally down a nerve and to the skin. If anything it will boost your immunity to shingles/chicken pox during pregnancy.