Pics are not clear enough to say what are they. But they are 100% not aefw. Acropora eating flatworm like the name says, you can only found them ON Acropora, and they almost transparent.
You can siphon those flatworm out as much as you can, then dose Salifert flatworm exit (its totally safe for fish and corals). Do water change then add gac after dose.