If you shoot tonight, you can get back to your regular shot time by shooting early 15 minutes per cycle OR 30 minutes once a day.
For example, tomorrow morning's shot would be 2 hours 45 minutes late. Tomorrow night's shot would be 2 hours 30 minutes late.
Since Lantus can last 12 hours, shooting earlier than that can act as an increase.
If you cannot be that far off schedule due to work, it might be best not to shoot tonight.