Weird Thigh Rash

Ok so I'm a little bit curvy and whenever I wear dresses/skirts I get this really awful chaffy rash sort of thing where my thighs touch. Sometimes it gets to be straight up painful. I don't know how to prevent it really besides putting deodorant on before hand and even that wears off by the end of the day. And I'm not really sure what are the best solutions for making it heal and not hurt. Please help.