From what I understand there was heat damage around the engines.
The good news there is that it might mean the rocket can be rehabilitated if needed since structural damage would be less likely.
According to the latest Musk tweets today's rocket was actually somewhat damaged in the landing - the scrificial "crush core" was, well, crushed.
The good news there is that it might mean the rocket can be rehabilitated if needed since structural damage would be less likely.