Are you talking about one of these?:
Designed to join bullnose radius worktops with all major worktop brands.Perfect alignment and fit with worktop. Light & strong aluminium in matt black finish. 630mm long easily cuts to length required. Universal left or right fitting.
orion.supplies
You could conceivably fit one in there but I can't see how it would fix anything or improve the appearance, so don't see the point.
As for removing the blown chipboard to make the top flat again....I think this is something that is possible in theory but in reality it would be so labour intensive you'd be better off just replacing the whole thing.