Is it possible that a person become temporarily blind after an explosion?

Yes: A flash from an explosion could temporarily bleach out the light sensing cells in the retina, causing temporary blindness. If bright enough, however, such a flash could even cause permanent damage.

Yes: There is a force or shock wave that goes out. Much depends on the type of explosion, the energy, and the shape as well as the closeness. This can causse retinal edema or even concussion to the optic nerve. There is also the question of defining temporary.