Throat aches from oral

I decided that there is no reason for me to ever have an unanswered question floating in my mind, since I found this site! I am addicted.
On some occasions I notice that my throat hurts either about an hour (if I am awake) or the next morning after performing oral sex on a significant other (I am usually down there at least 30 minutes every time).
Questions:
Why is this?
Can this cause any long-term damage?
If I swallow the vaginal juices, is the acid eating at my stomach?