  The Standard Model Higgs potential becomes unstable at large Higgs field
values where its quartic coupling becomes negative. While the tunneling
lifetime of our current electroweak vacuum is comfortably longer than the age
of the universe, quantum fluctuations during inflation might push the Higgs
over the barrier, forming patches which might be lethal for our universe. We
study the cosmological evolution of such regions and find that, at least in the
thin wall approximation, they may be harmless as they collapse due to the
backreaction of the Higgs itself. The presence of the Standard Model Higgs
instability can provide a novel mechanism to end inflation and to reheat the
universe through the evaporation of the black holes left over by the collapse
of the Higgs bubbles. The bound on the Hubble rate during inflation may be
therefore relaxed.
