Why do i keep getting cold sores?

about 2 weeks ago i got a cold sore in the front of my mouth (where the bottom front teeth are) on the right side. it took it...i think almost about a week to go away. for a couple days i was cold sore free then another one comes up on the other side of my mouth near the inside of my lip its still there & i have... show more about 2 weeks ago i got a cold sore in the front of my mouth (where the bottom front teeth are) on the right side. it took it...i think almost about a week to go away.
for a couple days i was cold sore free then another one comes up on the other side of my mouth near the inside of my lip its still there & i have been using a medicated lip ointment that usually helps with that stuff.
why have i been getting these cold alot sores lately??
I already got tested for herpes and it came back negative so what could it be?
do you think i need to be tested again? what are the ways of testing for this?
i have only been with 2 ppl in my entire life 1 of whom i am still with and have been for the past 6 years. we have never had herpes
im worried :(
Update: sorry sorry sorry.....i think its a canker sore
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