It is imperative to retalitate immediately while maintaining the context of self defense. Letting someone abuse you without consequence sets you up for the same abuse again later. Getting into a brawl and doing damage to your aggressor, even if it means getting bloodied yourself, will not only earn you the respect of others, but it will also tell them you will not take abuse without giving it back. In the long run, it will save you grief.

Always claiming self defense legitimizes your action should legal considerations arise. Everyone has the right to defend themselves, and if legal authorities say you should have run away, the response should be that you were prevented from doing so, whether that was pain, no opportunity, shock, or physical problems of some sort.