Ceiling medallion installation

[shan2themax]

What should I use to attach this ceiling medallion?
When I replaced this ceiling fan, and put a new one up, the bell shaped piece at the top was smaller, so the hole in the drywall is a little bigger than the that piece. I am DEFINITELY not dry-walling up there. I am just not sure of what type of adhesive to use. I know that I can drill pilot holes and attach to the box, but Idk that I want to do that.

Here is a pic of current ceiling and the medallion i am going to use. (I am going to paint it)

 

[bud16415]

https://www.acehardware.com/departm...olIvzyJ_TDIFJcR0CAxoCCo4QAvD_BwE&gclsrc=aw.ds

 

[shan2themax]

I found some stuff I already had and used it. I decided to use it with the ceiling light I installed today, even though I bought it for the ceiling fan lol. Anyways, it is still attached from this morning. Hopefully it stays. I will take a pic once I get the light hung.