Nose piercing is irritated?

I got my nose pierced about 4 months ago. I changed the nose screw stud earlier today and later on I decided I wanted to put a hoop in. I got it into the hole but I couldn't get it to go in any farther. I know the piercing is irritated but when will I be able to attempt changing to a hoop? (I put the stud back in) And does anyone have any tips for getting a hoop to in easier?