With Lantus, you want to look at how low the cat goes on a dose and not how high the cat is. It is obvious with the 48 that the dose is too high.
What you may see in the next few hours is a high bounce from the low number the cat threw this afternoon.
A bounce is when the body realizes that the Blood Glucose has gone too low and panics, dumping a whole pile of glucose into the system. Bounces are temporary but can take a few cycles to clear.
You are coming up to shot time soon. I'd suggest getting a test one hour before the shot (+11), then post that number asking for help.
If you can manage to do pre shot tests and then a few mid cycle tests (at night and on days when you are not at work), it would give you the background you need to keep your cat safe.