That doesn't necessarily mean brain is smaller (though it might), just that the rest of the face extends forwards further.
And since it was brought up in this thread, brain size is not necessarily tied to IQ as well. For example, brain sizes have been shrinking for the last 40,000 years: https://www.discovermagazine.com/planet-earth/the-human-brain-has-been-getting-smaller-since-the-stone-age Does that mean stone age people were smarter than us? It's doubtful because IQ gives such a huge advantage for survival, that at least until recently, the smarter ones were probably more successful in reproducing and protecting their lineage.
While front lobe damage may actually occur (haven't looked into it), even if it did, it wouldn't change the skull shape I think.
And if your brow is thicker, it gives your skull a slanting shape. Look at people with acromegaly: https://en.wikipedia.org/wiki/Skull_bossing#/media/File:Acromegaly_facial_features.JPEG
That doesn't necessarily mean brain is smaller (though it might), just that the rest of the face extends forwards further.
And since it was brought up in this thread, brain size is not necessarily tied to IQ as well. For example, brain sizes have been shrinking for the last 40,000 years: https://www.discovermagazine.com/planet-earth/the-human-brain-has-been-getting-smaller-since-the-stone-age Does that mean stone age people were smarter than us? It's doubtful because IQ gives such a huge advantage for survival, that at least until recently, the smarter ones were probably more successful in reproducing and protecting their lineage.
EDIT: Racial differences in IQ are entirely possible, but head shape and brain size aren't the evidence for it.