The blister type rash sounds like yeast to me. I would take her to the Dr. to make sure. If you can't then you can sometimes use over the counter yeast treatment in a VERY small amount. I only do this if it is soooo bad on a friday that it can't wait until monday to be seen. Yeast is a common rash problem that is sometimes mistaken for a normal diaper rash. If I were you I would have it checked out.