Hey Im 17 Years Old And I Only Found Out

hey im 17 years old and i only found out that you could roll back your foreskin to clean your glans a few days ago, my glans had never came out during erection. So i have been doing stretching exercises by retracting it in the shower and it doesn't hurt and it was getting looser. However yesterday i left my foreskin retracted for around 4 hours and it won't go back over my glans.