Remove the drawer from the furniture. Turn it upside down on a piece of newspaper under a heat light. The drawer needs to dry out completely before you try the paraffin. Let it dry for several days up to a week depending how moist the wood had become.
Try sliding the drawer into the furniture. Sometimes just drying the wood is enough to encourage it to slide. The swelling may have receded enough. If the drawer is still sticky remove it and turn it upside down on a firm, flat surface.
Rub a piece of sandpaper over any burs or splinters that are on the runners of the drawer. These are simply bars on each side of the drawer. Imperfections can keep the drawer from operating smoothly and need to be removed to make a flat surface on which to apply the wax.
Turn on the hair dryer and hold the stick of paraffin over it for two to five seconds. You don't want to melt the wax or it will be difficult to apply but you do want to soften it so it will slide onto the runners easily.
Apply the wax to the runners when it is slightly soft. Drag the wax stick over the wood as if you were rubbing a crayon on it. Also apply the wax to the glides on the inside of the drawer. It works on plastic, metal or wood glides. Think of it as lubricant. Push the drawer back into the furniture and move it in and out a few times to check that the drawer now operates smoothly.