According to the data you reported, you might be experiencing phimosis. Phimosis is a condition in which the foreskin can not be completely retracted from the head of the penis.
Circumcision is the most often surgical solution. Other surgical treatment for phimosis is preputioplasty, in which a limited dorsal lit with transverse closure is made along the constricting band of the foreskin.
Before trying for surgical treatment, you might want to try some non surgical treatments. Stretching the foreskin manually over a longer period might make additional foreskin to grow and thus to loose and to create a larger hole.
Applying topical steroid cream for 4-6 weeks to the narrow part of the foreskin might also be helpful.