Matrosect

Hi there, I made a new archetype: The Trollge. These monsters will rely on themselves or other monsters to be Ritual Summoned, without a ritual spell. (Sorry, this will be two cards) For example:

Hi there. I am having trouble with Skill Cards. I have a friend who says that once a skill card is flipped back over, it cannot be used again. Take, for example, Kaiba's skill card: Beatdown!. When it says "At the end of your turn, flip this card over." If I do so, am I allowed to activate the Skill Card again, or is that just useless text?