It would have the same mass, and it would be tiny -- like the size of a hydrogen or helium atom. AFAIK an asteroid mass black hole wouldn't evaporate yet since

It would have the same mass, and it would be tiny -- like the size of a hydrogen or helium atom. AFAIK an asteroid mass black hole wouldn't evaporate yet since the CMB is still warmer than its Hawking temperature. Very tiny black holes would have evaporated earlier in the universe. A black hole evaporates when its Hawking temperature exceeds the ambient temperature.