Hi @sharon8 ,
First check my comment (2 above yours).
You may also have to dis-assemble the camera to check if any damage caused by the leaking battery has occurred.
If you see any corrosion etc try gently cleaning it off using Isopropyl Alcohol 90%+ (available from electronics parts stores) and a Q-Tip.
Here are a couple of links that may be of some help.
[[Topic:Fujifilm Instax Mini Eight]]
This link is also helpful as damage caused by corrosive acid is likely to be worse than the corrosive effects of the impurities in water
[[Electronics Water Damage]]