there is still moisture in the case. put it in a bag or container of instant rice for a week or 2. the rice with dry it out completely. than it should work again unless the battery in the case got damaged. you can buy these and replace it.
https://www.youtube.com/watch?v=StGaoAxv9dk
the numbers on the battery will help you order a new one normally $5-$10 with shipping from aliexpress.com