One thing is just to keep them clean and they usually heal faster, but if you need it quickly covered up use concealer or other skin make up. It doesnt "cover them" but they make them seem older. Im just speaking from expreinces I had and what I did to hide them not as noticable
Sometimes if you slap on a bandaid or something and just say you fell or something that sometimes works for me! (My parents used to check my arms and stuff)