Thanks for sharing your problem with us.
I have gone through your concern, Generally milk tooth don't hurt that much during exfoliation. But if the tooth is traumatized it can hurt him.
Until you visit the dentist
,try to keep noticing the tooth,don't touch or move it.
Keep notice on cleanliness of mouth and also gargle helps in reducing the infection.
As per chances of choking
you have to monitor for him,though chances are less
and try to visit the dentist as soon as possible.