Welcome to Health Care Magic.
Tears of foreskin is a common problem among men especially when someone is sexually active or if you stretch it too far . As you have have mentioned that the tear is small , there should be no problem and will heal normally.
It might take 10 days for it to heal completely.
A small suggestion please use a lubricant while stretching to avoid such tears.
And be careful as to not forcefully retract the prepuce ( foreskin) which might lad to srious problem called Paraphimosis
( Foreskin can not be protracted).
If the problem is severe better consult a surgeon and undergo Circumcision( it is a minor procedure hardly takes 20 mins for the surgery).
Wish you a very good health.