If the metal got to the various journal bearing inside the engine (cams, crank) then engine failure could be down the road. There are numerous posts here that outline what happens after a turbo failure, what can be done as a precaution, and what to look for.
Very basics: Full oil system flush, inspect oil pan, replace oil cooler, replace all oil lines, inspect intercooler for debris, flush oil system again.
If you do this will your car be free from failure down the road? No. These step WILL help to ensure that no additional damage is being done. Also, track down the failure mode of the first turbo, as this might give you a heads up to other problems unknown to you at this point.
Best of luck.