I would start by opening the unit and checking for physical damage/corrosion.
If things look good in there, I would still do the hot/dry rice thing with it. (even though it's been a while)
1 heat a bowl of rice a few times to dry/extract moisture
2 sure your happy its quite dry
3 submerge all the parts in the warm rice for a day or two
That would help extract any moisture trapped under IC's and inside displays.