According to your sign and symptom you are suffering from fear from hair wash in the night due to upcoming cold .
As you know that best treatment depend on the correct diagnosis and correct diagnosis depend on the complete history of the patient so please take consultation from a doctor and give complete history of the patient to make correct diagnosis and then best treatment will be start.
Next Steps
You can use warm water in the cold weather.
I also wash and bath in the night everyday but with the warm water.
Health Tips
It's very good to follow hygiene to prevent any infection.
Cleaning is very good habit.
please follow that for until last breath.
please keep positivity to fight any disease and any problem of your life