The first thing is you need to get him checked by a vet.
It could well be linked to the fit that he had (maybe he had had other fits before).
Secondly you need to see a reputable behaviourist. If you do the wrong thing now (like holding him down on the floor) it could well escalate the aggression and you could end up being badly bitten.
You could post on this forum:
http://ttlntl.co.uk/forum/
They have behaviourists on there that will offer advice - it is totally free to join.
This is one case on there (about a rough collie):
http://www.ttlntl.co.uk/forum/index.php?topic= 1301.0