I would take the battery out (it’s screwed in on the back), and take a blow dryer to it on the cool setting. Also check for water that might have gotten in the battery slot. If you have a tri-wing screwdriver (the tip looks like a “Y”), carefully open up the back of the DS and check for any water that might have gotten in the system. Blow dry that too. It might be beyond repair, but it is certainly worth a shot. If it is dead, consider selling it on eBay as broken. There are a lot of people who use various parts in broken DS’s. You might not get a lot of money for it, but at least you’ll get something.