I been doing stretches to loosen my foreskin. Recently I've pulled it back but it won't go back over what do I do.
go to a doctor ASAP
Relax, draw all the loose skin of the shaft of your penis from the base of your penis and draw it away from your body, slight lubrication such as baby oil or liquid coconut oil may help. Also training cold water from a shower head may help.
The recommended method is a squeeze technique where you squeeze the head of the penis between thumb and forefinger - it may hurt intensely for a second but this usually solves the issue.
The problem is known as Paraphimosis …
As Dugie says, though I found my foreskin retracted better when I was in the bath. I had tight foreskin issues from aged 13 up till my late twenties and continual stretching eventually fixed the problem.