I found the number of a SA health line for a Parent Helpline on the internet - 1300 364 100. Or you might have a similar number that you know of. Why not try calling them and see what they say?

If in doubt, a trip to emergency - as I've pointed out to dh when taking our kids to emergency, kids can go from 'meh' to 'uh oh' in a pretty short time, so if you're not feeling good about this, then just nick down with him.