1- Currently, your ears only ring if you are blinded by the flash. You should be able to hear one go off from more than a hundred meters, so you should prolly' be deafened even if you aren't looking at the flash, and for a lot longer. Also other sounds should be muffled when you can start hearing again and fade out eventually.
2- When you get flashed, I'd would lower the amount of time you see just white, and lower the intensity of the accumulation-motion-blur a lot slower, so after the afterimage, things would still be blending into eachother, but you could still see.
3- If flashed, the colors on your screen should probably be altered a little, eventually returning to normal.
4- If you a lil' far away and arent hit by the whole flash, than it should probobly leave a little spot in your vision where all the flashbang effects could be. Try looking at a bright light for a second. (Not too long. Don't hurt your eyes.) You should see the point of that light burned into your vision for a bit. I drew an example of this anyway.
Also tinnitus. If ANY explosion is pretty close to you, than you should probobly get a little bit of it. I'm assuming the soldier dudes are wearing ear protection, but I'm just assuming explosions are loud enough to get ears ringing anyway. I don't have any evidence to back me up on that though.
(Below-Flashbang part-vision-burn example. That flash should be farther away or something but whatever.)