My son has scratched my wok. Now it's rusting. Can it be restored or should I throw it away?
Yes, you can restore it.

Clean the whole wok. Wash with soap and dry it. Apply a small coat of oil and put it on high. Let it burn (ventilate the kitchen).

Repeat the process of applying a small coat of oil and putting it on high another two or three times.

Done.

Edit: As noted by @GdD, this method cannot be applied to non-stick woks.