My foreskin won't cover my glans. Is something wrong?
I am assuming you are uncircumcised and that your foreskin once completely covered your glans, but doesn't do so any longer. When you were a child, your foreskin was quite large and your penis was quite small. The foreskin was like an oversized tee-shirt that hung far over the end of your penis. About mid-way through adolescence your penis grows to its adult size, but for many men, the foreskin doesn't grow as quickly. It is normal for uncircumcised men to have their glans completely covered or to have a portion of their glans poking out of the end of their foreskin when flaccid (not erect).
A few men have problems after having an erection of having their foreskin stay back instead of sliding back into place. You can manually slide it back into place, or if it seems too tight you can do stretching "exercises" for the foreskin to encourage it to loosen up. One stretch is to take the foreskin and gently pull it away from the body as far as it will comfortably go (it goes a surprisingly long way). The second is to work your fingers between the foreskin and the glans and gently enlarge the opening as far as comfortable. You will need to do these stretches several times a day to make an effect.