I again offer the idea that Mexican Pinguicula do NOT need to be dried off. In the 10-12 years that I have been growing a widely varied and fairly sizeable group of them, more whenever I can get them, or create them -- I have nearly always kept them in trays of water. I have played with the concept of letting them go dry, but not absolutely dry. Whenever I've done this, I often lose some of those treated this way to rot and death. Needless to say, I avoid letting any go dry for long.
Here is a photo of some of my WET, Mexican Pinguicula. BTW, when you see any of my photographs of these plants, you can assume they are sitting in trays of water, they are.