Batteries will become unfit to use after they’ve been in the water. Usually however, a battery won’t leak inside the washing machine thanks to the safety valve - so chances of your textile being affected are minimal.
As zinc air hearing aid batteries operate differently than other batteries they have different characteristics. In winter, rooms may be drier, warmer or badly ventilated. These effects can disturb the performance of your batteries.
Whereas some size change is perfectly normal, it should not be overly pronounced. If so, replace the battery immediately. A bulging coin battery may lead to device malfunction and even short-circuiting.
A battery is a chemical product which produces electricity by chemical reactions at its inside. These reactions and its inside materials do deteriorate over time. If you start using it within that period, the battery will operate normally and maintain the specified performance.