My son, at 12 years old has a tight foreskin, to the point where it does not retract at all.
He has had no cuts or injuries to the foreskin or even his penis.
Should i be worried?
No, it can be stretched by inserting your little fingers into the tip during a bath or shower so it's warm and soft and applying some pressure to pull it open. Do this for a few minutes at every bath and it should show some improvement in a week or more. If you/he can't get two fingers inside you can pull back on it when he has an erection to accomplish the same stretching until two fingers will fit.