All battery manufacturers warranty the batteries from leakage and the damage if causes. Look at the website for whoever made them and contact customer support. They will usually replace or repair the device so long as you send it to them.
If you are able to un-screw the cover with a little force, use some white vinegar and a cotton swab to clean off any corrosion that might be left on the device. Be cautious as alkaline corrosion can burn your skin. Allow to dry thouroughly before re-use.