There was a small blister a week ago. Last two days the area surrounding has becone red and tight snd is extremely painful. I am able to sit properly. I had a similar issue earlier but those blisters had puss and once ruptured will heal fast. This one didnt grow that big but yet painful . I was put on antibiotic and zinase last time. Bloods tests were dobe ladt time to rule out simpmex virus last time. My sugar levels fluctuate between 100-109. My doc said its preduabetic stage.