Whatever you do, do not remove any leaves, your plant needs them as a VITAL source for energy production. Your plant will still grow ok and flower just fine and beside what your friend thinks, you will still get a reasonable harvest, maybe a little later than originally, but still a harvest. It will take your plant about 2 weeks or so to sort it self out/recover from this traumatic injury, but she will give you a crop to be proud of none the less. Just remember, those healthy green leaves are of VITAL importance to your plant for energy production. As she has lost much of her top section, there would be a loss of capacity to make energy/photosynthesise associated with that, so she needs every single leaf she has left to make the energy to help her recover and to be able to grow her best and biggest flowers. Please ignore any advice that defoliation makes your buds grow better or other such nonsense, your buds need all the leaves possible to produce the energy needed for flower growth.
Hope this helps,.... Organoman.