Hi
It seems you have what is called paraphimosis. It is a condition where in patients suffering from phimosis(tight foreskin), the foreskin goes back gets swollen and cannot be replaced back.
Next Steps
This needs to be dealt with urgently- please see an urologist who will reduce it for you. Your will also need circumcision at a later date.
Health Tips
You could apply ice packs to the area to reduce the swelling which will also help the urologist in reducing the paraphimosis.