Sometimes when i sneeze or blow my nose hard, i see many small sliver/grey specs fly across my field off vision. this usually lasts anywhere between 5-10 seconds. what is this and is it something to worry about? thanks.

No worry: Sneezing and blowing your nose creates an aerosol and it is a natural phenomenon. This is one of the reasons for recommending wearing of masks to prevent spread of Covid-19. Have a healthy diet, exercise 30 minutes/day, drink plenty of water, have safe sex, no tobacco alcohol weed or street drugs. For nutrition: http://www.choosemyplate.gov/. Get HPV vaccine. Wish you good health!