Lines going down screen.

Please help! My phone is constantly displaying lines from top of the screen to the bottom, if I rotate my screen the lines move to go from top to bottom.

They are always there but less visible when the screen has mainly white or black images to display. When there are coloured images, the lines are very prominent.

I did briefly touch my phone when my hand was wet so it's probably water damage.

Does anyone know how to help me?