The water causes corrosion and provides circuit paths for the electricity which were not in the phone's operating design and could damage the components. The corrosion starts immediately and doesn’t stop until it has been properly cleaned away.
Rice does not fix the problems caused by corrosion Rice is for dinner, not repair.
Do not try to charge or to turn on the phone and remove the battery as soon as possible so as to minimize any further problems.
Then you need to disassemble the rest of the phone and clean all the affected parts using Isopropyl Alcohol 99%+ (available at electronics parts stores) to remove all traces of corrosion. 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 concentration (%) 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 any shields that may be covering some components as the corrosion may be under them as well. Also the ends of any flex cables and the connectors need to be cleaned as well.
Hopefully after you have done all this the phone might possibly work correctly again.
Here is a link to the ifixit Huawei Honor 8 repair guides that may help.
If this process seems too daunting, take your phone to a reputable, professional 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. It isn’t going to fix itself.