Usually the vitreous 'settles' and an equilibrium develops and the flashes stop or improve. If they worsen: more flashes, more floaters, loss of peripheral vision you need to see your ophthalmologist immediately.
a phosphene is not that bright so calling it that would be incorrect. Flashes of light that bright could be caused by a posterior vitreous detachment (PVD) putting vitreous traction on a dark adapted ultra-sensitive retina. Cataract surgery often causes the vitreous to shift or move causing flashes at night.