I inhaled a little something when i was eating sunflower seeds, not a whole shell but something small. could this cut my windpipe and cause scaring?

Aspiration : Highly unlikely to cause major injury. Should clear with cough. If symptoms persist beyond a few days, get a chest xray at your doctor.

No: If you scratched your esophagus or trachea this will be a nagging pain that should go away with time, several days to a week. This should not cause serious damage but if pain persists after a week go see a doctor for a look

Aspiration: It can cause a cut and irritation but this usually heals up without any major residual effects.