  The back reactions of Hawking radiation allow nontrivial correlations between
consecutive Hawking quanta, which gives a possible way of resolving the paradox
of black hole information loss known as the hidden messenger method. In a
recent work of Ma {\it et al} [arXiv:1711.10704], this method is enhanced by a
general derivation using small deviations of the states of Hawking quanta off
canonical typicality. In this paper, we use this typicality argument to study
the effects of generic back reactions on the quantum geometries described by
spin network states, and discuss the viability of entropy conservation in loop
quantum gravity. We find that such back reactions lead to small area
deformations of quantum geometries including those of quantum black holes. This
shows that the hidden-messenger method is still viable in loop quantum gravity,
which is a first step towards resolving the paradox of black hole information
loss in quantum gravity.
