Hi there! Last week I started preparing my Prindle 18-2 for summer and I discovered some small blisters which seem to have humidity/water. It is a bit weird because I stored the boat just as I store it every year. A friend told me that the hull could have been humid inside and freezing temperatures could have formed tiny cracks...What is also weird is that they seem to be receding now that the boat is standing in the sun and all that is left is what you can see in the picture. Does anyone know what this is and what has to be done about it? Thanks in advance!