I used to have blisters in my mouth since my childhood, about 7 months ago I had teo blisters in my throat they were very painful doctor gave me high potency antibiotic due to blisters could?t drink enough water and had hepatitis a but blisters were gone after some time now again I got blister in my throat deep inside need to know why I do got blisters? Also I am a smoker and for the past 2,3 weeks could?t drink much water.