The impurities in liquids causes corrosion and provides circuit paths for the electricity which were not in the tablet’s operating design and could damage the components. The corrosion starts immediately and is ongoing until it has been properly cleaned away
First do not turn on your tablet and then you need to remove the battery as soon as possible from the tablet to minimize any further damage.
Then you need to dis-assemble the rest of the tablet and clean all the affected parts using Isopropyl Alcohol 99%+ (available from electronics parts stores) to remove all traces of corrosion and any remaining liquid. Do not use "rubbing alcohol" as in some cases this is only 70% IPA or less, can contain additives and is not as effective. If you do have to use it, check the label to verify the amount of IPA. The higher the percentage of IPA the better
Here is a link that describes the process. Electronics Water Damage
As always with electronics, especially surface mounted pcb, be gentle when handling and especially when brushing away the corrosion. You do not want to remove any components from the board. You will also have to remove the shields that are covering components as the liquid may have got in under them as well and clean away any corrosion that is there. Also disconnect any flex cables and clean the cable ends and the connectors.
Hopefully after you have done all this the tablet might possibly work correctly again.
Here’s the ifixit Kindle 3 Repair guides which may be of some help
If this process seems too daunting, take your tablet to a reputable, professional electronics or mobile phone repair service, experienced in liquid damage repair and ask for a quote for a repair. If you decide to do this, do it sooner than later.