Blood clot in posterior to the retina due to blunt injury to the eye with loss of vision. Pls tell me if the vision comes back or not?

Depends on damage. . Traumatic retinal hemorrhages can range from superficial to catastrophic. If there is too much damage to the retina or there is blood underneath the retina, the damage may be permanent. In that case, the vision may not come back. See your retinal specialist for more specific information.
Depends. A blow hard enough to disrupt vessels under the retina, will likely have caused some damaged to the retina itself. The clot disturbs the nutrition of the retina and moves it out of focus. Given some time, this will absorb and then you can see what vision is remaining. You should be followed by a retina specialist.