I have dark circles under my eyes and concealer doesn't seem to cover it and it wipes off after a few hours. Is there anything else I can use/do to hide them?

Soak cotten wool pads (the ones you use to remove make-up) in milk leave them in a bowl in the fridge for a while or even the freezer to cool them quickly and then lie down relax and put them over your eyes for about 15mins or more if you want, that should get rid of puffy/dark circles

if your trying just normal block conceler, i reccommend a cream conceleer specially formulated for under eye bags. the touch eclat by YSL is good for that.
also, try using two teabags then putting them in the fridge for a few hours then put them oer your eyes.
the caffine will de-puff your eyes.
you could try cucumber as well.
you may not be tired which is what people put under eye bags down to, but it can be a genetic thing as well.

Dermablend is the absolute best, but it's about 18 dollars and you can find it online or at a department store. I believe it's water proof too so it shouldn't wipe off. Or try an under eye illuminater which a lot of brands make.
Good Luck!