dehumidifier or humidifier?

hi mummies , i would like to ask if i should use a dehumidifier or humidifier instead my room has no windows as there’s a partition up and the window is at the other side and it’s locked up because of a window cassette aircon. the window can only open up to a palm size so totally no wind / natural air will go to my side of the room. my baby is always sweating at night and it’s super stuffy he always wakes up. should i get a dehumidifier or humidifier?