Don't use "lemon oil" unless you really want to clean the board. You never know what's in that stuff--- pressed lemons and most of the time also some sort of mineral spirits or naptha. It is by design a degreaser, meaning it pulls the oil from the wood in the process of cleansing. Your board is clean but dry.
If that is your goal, have at it. If you want the board to look darker and feel slicker, try Fret Doctor. I also like Lizard Spit fretboard conditioner and have heard good things about Gerlitz Guitar Honey. I want my rosewood to look like a smooth, dark, vintage played-in board. So I never use lemon oil.