I have been living with what I believe to be HSV-1 for several years now. I have not actually gotten tested to confirm this but I get cold sores a few times a year, and they only appear on my bottom lip. 

I have just recently gotten over an outbreak (about a couple of weeks ago). About 7 days ago, I kissed (made out) with someone I had never kissed before. About 4 days after this I experienced another breakout on my bottom lip. I was kind of surprised about this as I had just gotten over an outbreak a couple of weeks ago. I reasoned that this shouldn't have happened because there should still be some left over resistance (antibodies?) from the first outbreak.

I also thought it was strange that this second outbreak occurred about 4 days after I had kissed the person mentioned above. I've read that this is the average incubation time for a new HSV infection. The second outbreak was a little more aggressive than what I'm normally used to. 

Could this second outbreak be a result of a new infection?  Are there different strains of the HSV-1 Virus?  Or could it be that I've acquired both HSV-1 and HSV-2 in the oral area? 

No, it is VERY unlikely that you would acquire a new strain of the HSV 1 virus.  While that is not impossible, it is still far more likely that you simply had another outbreak.  HSV 2 is uncommonly oral and when HSV 2 does live in the mouth area, it is rarely shed from there so I would take HSV 2 acquisition from kissing off our list. 

The most likely thing here is that you simply had another outbreak. It is also possible that you were shedding around that time so you might want to touch base with that person to see if all is well.

Terri