I dont know what I should do. Please help because i a bit of a freak when it comes to my hair?

Ok. so i tryed some thing new and i washed my hair as normal then i put my conditioner in but instead of washing it out after a few minutes i put on a shower cap and i let it soak i my hair over night. I am always fixing my hair and tryin to make it as healthy as possible. so my question is.... should i rinse out the condition or leave it in. if i leave it in will my hair be shiny or will something else happen. please help!