if there's no seal/sticker and it seems easy to disassemble (not all glued together), i'd just take it apart and wipe out any moisture with a microfiber cloth or something very soft and lint-free. watch out for micro scratches. this is likely to be the most efficient use of your time. maybe that will be the end of the problem.
otherwise, if it bothers you, try warrantying it. **** dewalt, you don't owe them anything.
on the other hand, i just don't know anything about their warranty process. does it take like 6 months? are you likely to get it back in worse condition than you sent it out in? some warranty services are a complete joke, so take that into consideration.