If it is a chalazion, then you don't want the child to have surgery when it might get better on its own. That's just common sense - again provided it is indeed a chalazion. I think the CT scan is a good idea, in order to rule out orbital cellulitis and/or severe sinusitis and preseptal cellulitis. Depending on blood tests, if there is fever, how CT scan look, then doctor will have better idea how to proceed.
MJK MD