I was hoping for more information from you. I'll give you a preliminary answer, however, and then you can ask a follow up and I can add further information if I haven't fully addressed what you want to know.
Since the injury here consists of bruising and you did not use a weapon, if this woman goes to the police and reports this incident, you would likely be facing a charge of misdemeanor assault This would be true even though the incident took place in your home and that you asked her to leave before matters got out of hand.
This sounds like it would likely be charged as a class 1 misdmeanor, which would have a maximum possible penalty of 6 months in jail.
If you wanted to go all the way to trial on this case, it sounds as if you might have a self-defense claim. That won't stop you from being charged and prosecuted. But if a jury believes you hit this woman because you reasonably believed you were in imminent physical danger, that would be a complete defense to the charges. That said, as a trial case, this matter would likely come down to witness credibility. I would bet, for example, that the complainant would not say that he was trying to harm you first but will insist that you started it. So even though you know that not to be true, whether your self-defense claim will keep you from conviction, is going to be up to what a jury believes after they hear all of the evidence from both sides.
If you don't want to go to trial and risk 6 months in jail if you fail to convince a jury you only acted to defend yourself, then under the facts and circumstances of this case, your lawyer may very well be able to get you a special deal such as a diversion or a deferred adjudication. This is where you are placed under supervision, must stay out of trouble with the law, pay fines, do community service and perhaps also take anger management classes. If you complete your sentence successfully, charges are dismissed so that you don't have a crime on your record.
Either way, if this matter comes to court, you should retain a criminal lawyer to help you fight the case.