(From the book 'Black Holes and Warped Space-Time' written by astrophysicist William J. Kaufman, III, the Bantam edition published in May 1980) Black holes lose mass with time. Temporary particles and their corresponding anti-particles that appear and then disappear happen everywhere, all the time.
If one such pair appear at the event-horizon of a black hole, and one particle gets pulled in but the other does not, then they do not disappear again. Since mass-energy cannot be created or destroyed, the mass of the particle that stayed outside the event-horizon is subtracted from the black hole. The smaller the black hole, the greater is the ratio of the surface area of its event horizon to its...

(From the book 'Black Holes and Warped Space-Time' written by astrophysicist William J. Kaufman, III, the Bantam edition published in May 1980) Black holes lose mass with time. Temporary particles and their corresponding anti-particles that appear and then disappear happen everywhere, all the time.
If one such pair appear at the event-horizon of a black hole, and one particle gets pulled in but the other does not, then they do not disappear again. Since mass-energy cannot be created or destroyed, the mass of the particle that stayed outside the event-horizon is subtracted from the black hole. The smaller the black hole, the greater is the ratio of the surface area of its event horizon to its mass, and the faster it loses mass. Small black holes will disintegrate into a countless numbers of subatomic particles in femtoseconds or less. There is not enough time for a CERN created black hole to suck enough matter into itself to overcome the loss of matter from all these particles created from event-horizon 'events'. This also explains why all the small black holes that must have been created during the Big Bang are no longer around; they have already disintegrated into sub-atomic particles long ago.