Probably a good idea to replace the oil & filter with some good quality semi synthetic and keep an eye on the level.

Water getting into the filter and possibly the engine (in small amounts) will just get thrown out through the zorst valves etc, so you might seem some steam in the exhaust outlet for a short while along with a bit of a cough... I'd suggest you clean the filter, oil it and clean out the airbox and drain pipe too if you're worried.

If it's running OK now and the plug looks like it should, you've probably got away with it. Too much water in and she'd of died or hydraulic locked on you and you'd have known about that..