For the Vietcong Tet was a massive defeat, very little support was gained from the South Vietnamese and 25k Vietcong were killed while 5000 were captured.
The Vietcong had been decimated.
This was a turning point for the US, Tet came at a time when there was growing disappointment, and the war correspondent had stated that the conflict had reached stalemate.
The US had no alternative strategy to military escalation, a strategy which'd failed.
And so Johnson's new Secretary of Defence, Clifford, advised de-escalation.
Tet was a psychological defeat and showed the USA that a quick end to the war with US victory was far away,
When Johnson did not stand for re-election, this marked a new point of Cold War action in Asia and the start of a new strategy.