Tight valves will hold one or more open even a few thou, will drop compression, running long like that also can burn them as stated and erode the seats. As long as it wasn't like that to long, maybe no harm done.
Sucking water in can also bend a valve, depending how much water and what rpm the motor was running at when ingestion occurred.
Oil consumption should have nothing to do with engine size or number of cylinders. Hour and mileage will , same with poor maintenance . Or in the case of my KLR, bad factory ring design.