Oral ulcers

I used to get oral ulcers very often, until I was at my wit's end and worried sick that I probably had a high tendency of getting oral cancer. Then I found that I did not have ulcers at all throughout my pregnancies. So it could be due to the multivitamin that I had been taking diligently, my body lacked of some minerals that I did not get from my diet so I had to rely on the supplementary food. So the ulcers came back when I stopped the vitamin intake. I have to remind myself to take it more frequently. These days, I have got one and it's so painful. Even I make taking multivitamin a routine, I still can't avoid getting ulcer. Thanks to my sons who are so active and restless. They bump their heads into my lips and that's how I get the ulcers.