Hurt putting alcohol on my blister. Poking the blister with a needle hurt too and why does my blister always itch?

Please Clarify. First, i doubt that any physician recommended you put alcohol on a blister. Second: what kind of blister and where is it? Third, is this herpes? If so, these blisters should be treated with anti-viral medications not alcohol. Fourth perhaps a visit to your doctor to learn skin or wound care is a good next step.
Don't know what area. Of your body the blister is. Recommend not breaking open blisters as this can make you more suseptible to infection. If you have recurrent unexplained blisters- would recommend evaluation.