Sleeping with wet hair can lead to a number of potential harms, including:
Development of split ends: Wet hair is more fragile and prone to breaking, so sleeping with wet hair can lead to split ends and other forms of damage.
Increased risk of infection: When hair is wet, it is more susceptible to bacterial and fungal infections. Additionally, sleeping on wet hair can create a warm, humid environment that is conducive to the growth of microorganisms.
Development of dandruff: Wet hair is more likely to become oily, which can lead to the development of dandruff.
Difficulty sleeping: Wet hair can be quite uncomfortable to sleep on, which can make it difficult to fall asleep or stay asleep.
It is generally recommended that you dry your hair thoroughly before going to bed to avoid these potential harms.