I had surgery last week and a blister developed on the outer edge of where they placed this clear bandaid type stuff. I asked the nurse and she said some people have reactions to the adhesive. I had the bandaid things in several different places without any other blisters. After 3 days I used a sterilized pin to lance and drain it, now it is all black (it was clear before). Looks like a big blood blister. What's up?