Keeping water out from spark plug area
 

I went off roading the other day and went through a water hole, not too fast, but enough to splash water onto the motor. the engine then started to run rough as hell and stalled. Later on a buddy of mine scanned the code and found the #5 cylinder was misfiring.
Well after i cleaned it and stuff it ran fine and still is. My question is, is there away to keep water out of the crater looking place that the spark plug goes into?
Or has anyone else had this problem?

I think the coil should have a seal to keep water & dirt out of the hole in the head for the spark plug.

I'm pretty sure it does too. But it might have a tear or a crack in the seal. But water/mud definitely messed one of the coils up somehow.