Was the blinker itself impacted? The physical light bulb filament can be broken fairly easily.
However, assuming that the unit is not broken, the first plug to check would be where the flasher unit joins the wiring harness about 10-14 inches down the wire from the blinker. Make sure the bullet connector plugs are securely pressed together. To test the unit you could swap the blinker with the Front left blinker and if it doesn't work when up front the flasher is broken.
Hope you get it worked out.