Well, you could try pulling the dented piece of laminate out (try lifting it out with a craft knife, if that doesn't work then a dab of superglue and a bit of wood).
Once its out, fill the area behind it with PVA glue, stick the laminate back down, and weigh it down with a piece of glass, so you can check its still in the right position. Wipe off any excess glue as you're sticking it back.
Once its dry, use a razor blade to lift any dry glue, and a bit of fine sandpaper around the edges. You might have to coat it with a tiny bit of varnish to stop water getting in.