Yes! Your dashboard can be recovered, so long as the audit events of its previous saves have not been purged from the audit table.

1. Use SQL console to find the ID by looking through the context to find if that's the deletion event (changeType 3, where 1 is create and 2 is modify)
   select objectId, context from audit where typename='JSON_DATA' and changeType=3 order by id desc limit 10;
2. Create a new dashboard in the dashboard designer and save it
3. Find the ID of the new entry in the jsonData table via SQL
   select id, name, data from jsonData order by id desc limit 5;
4. Use the SQL console to change the ID of the new entry in the JsonData table to the objectId we found in step 1.
   update jsonData set id=[objectId from step 1] where id=[id from step 3];
5. Reload the dashboard designer page, and use the revert tool to recover the deleted dashboard!