I often use a fan to sleep, but you are right there are negative effects, the biggest one for me is a dry throat in the morning.
One thing I have tried is having a humidifier in the room too, this can increase the humidity, but sounds like you are in a humid climate already.
I've never used a humidifier before, but I heard that it's suitable for those who have frequent colds and dry throats. So it's a better option than using A fan. I think it will be on my next shopping list. thanks for mentioning it.