Take a reduced dose (say less than half of your usual dose) and then take your lantus as normal tonight, if you do just be careful of the overlap of the doses so you may want to monitor your bg levels a couple of times throughout the night, if in doubt contact your DSN who will advise further.
Take 2 units, as I said before there will be some overlap with tonight's dose so it's wise to be cautious, if you wanted you could just take corrective doses of QA insulin and just inject your lantus dose as usual, or you could move the dose back to 8pm, if in doubt do ring your DSN or diabetes clinic and ask for advice, this is what I was told by my own DSN if I missed a basal dose and remembered the next morning.
As you take the Lantus once every 24 hrs, if you missed the dose by 6 hrs take 3/4 of your normal dose, if by 12 hrs take half, if by 18 hrs take 1/4 (or don't bother). The overlap will last less long for the smaller doses. Only bigger doses act for the full 24 hrs. But as Noblehead says, pay attention to your BG.
Or alternatively as @noblehead says, just do correction doses until your next Lantus injection.