It happens! When we were using MDI I had my mobile phone alarm set to go off every night for the Levemir injection otherwise I'd forget. We used to split the dose, the breakfast one we didn't forget because she had it with breakfast but the evening one wasn't with a meal and we'd forget. Perhaps if you do something similar, have an alarm set, it will help avoid this problem.
I'm not sure about Lantus, we used to use Levemir. But I believe if you missed the night time you could split it fairly evenly in half and give that half the next morning. But keep a close eye on readings for the rest of the day. Correct any highs with Novorapid and any lows with the usual hypo treatment.
As you've done the full injection this morning you'll need to speak to your DSN as tonight is going to be tricky as to how much to inject. If you do the full injection then he may run the risk of going hypo during the night. She may suggest missing an injection again tonight, then tomorrow morning doing half the dose followed by the full dose that evening.