I wouldn't go back to the fitter who did our worktop!
Here are two photos. It's hard to see the indentation. It's deepest where the dark mark is (where the Formica chipped off), and there's a shallow slope down to that darker patch.
I've ordered some Formica samples so I can match the colour with ColorFill. The joiner doing the other job thinks this is worth a go and it may work, but I should practice first. He wasn't so hot on replacing the worktop.
One approach, suggested to me by another company, would be to 'burn off' or remove with heat (and acetone) the layer of Formica already on and attempt to re-apply a new sheet in situ. Perhaps this is possible, but it would be quite labour intensive. Perhaps I could do some of the prep work to save costs (we're broke) and have the expert in to fit the laminate - I've been looking at a few videos about the process.