I don't see a problem with drying up the wood. If anything, the neck has absorbed moisture from being exposed. Before sanding, I would clean the neck to remove hand oils and dirt. I would use lacquer thinner or acetone or both. I would rub down with clean cloths well saturated with the thinner. Once clean and dry, begin sanding with a block to keep it level. You may have to remove as much as a 1/32" or so to get down to clean wood. There are several good products for sealing and finishing the neck, once it is clean.
McD Custom Guitars