Hi welcome to HCM .
Cracker injuries should not be ignored and needs a through retinal examination to rule out Intra ocular foreign body. I would suggest you to get it examined by a Retina specialist, as what you are experiencing is called 'floaters' in eye,in simple words.
Sometimes, if a small particle ( like a cracker dust)enters forcefully, the entry point gets sealed quickly without causing any immediate reaction. It can stay quiet or cause an inflammatory reaction latter. The symptoms include redness
, pain on moving the eye, sensitivity to light, blurred vision
and flashes in eyes.
In any case the earlier intervention the best. So any floaters must be examined carefully at the earliest . Take care .