I'm not a physician or a pharmacist, but I'm a long-time diabetic.
I have read that mixing lantus
with any other insulins can result in unpredictable results in both the lantus and
... your daughter's case ... humalog
. Unpredictable can mean that the humalog
will not peak as expected (may be delayed) and
may also have a diluted effect.
Watch your daughter carefully for adverse effects. All should be fine by the time tomorrow rolls around.