Sounds like the 3M Nexcare Tegaderm bandages that I've used before. Been out for quite awhile. Never used them on a blister, but have used them on cuts and such. Work fine.

I don't think the bandages are treated with anything, they're simply designed to let your skin 'breathe' while sealing out moisture and dirt, allowing new skin to grow over the wound. The Nexcare bandages I've used have stayed on through showers and such.

As an aside, I had a bit o' skin cancer removed recently, and the post-op instructions had me cleaning and bandaging the surgery site daily, but specifically indicated not to use neosporin or other antibiotic ointments, just soap and water, dry, then apply a bandage.