To graze or scrape (one's skin), as when the surface of the skin is rubbed off by a fall or friction.
自転車で転んで膝を擦りむいた。
I fell off my bike and grazed my knee.
子どもが遊んでいて肘を擦りむいたので、消毒して絆創膏を貼った。
The child scraped his elbow while playing, so I disinfected it and put on a bandage.
階段で滑って手のひらを擦りむいてしまった。
I slipped on the stairs and grazed my palm.