Yes if they are just under the Gel coat which are the most common, as the hull dries the blisters will recede. You can usually tell there are voids by careful examination. If the blisters are deep in the laminate they usually take a very long time to dry out if not opened and drained. Drying out the hull depends on humidy and temperate. Search for osomosis on the web and you will find articles that may be of interest.