One last note - a healing corneal abrasion and herpes simplex infection of the cornea can look very similar - so that may confuse the doctor. The good news is that an abrasion will heal very quickly usually.
MJK MD
Usually you would have pain right away. I would go with whatever the ophthalmologist says here. The history is a necessary part of a good exam but can sometimes help and sometimes lead you in the wrong direction. The ophthalmologist will take your history into account but will also need to treat what he sees. Perhaps your pain is more from uveitis due to the contusion which would not come on for a few days. The small abrasion may be a secondary finding.
Michael Kutryb, MD