When your bag gets wet, keep things simple. Refrain from using things like hair dryer to evaporate the water, as this can alter the leather's properties, resulting in discoloration and uneven tightness. A dry cloth and airing the bag will do just fine.
If the leather gets too dry, you can purchase natural leather cream to apply on the bag to moisturise the leather.
In general, refrain from using detergents or chemicals. Use a damp cloth to wipe clean.