What Causes Mouth Ulcers And Pimples On Face?

I'm 34 years old and a non vegetarian. I'm having a controlled diet and are not taking too much spicy or non vegetarian items. I'm often having mouth ulcers and pimples on my face. Am also suffering from dandruff which I thought may help you if connected. Once I get some ulcers in mouth, it takes around 5 to six days to heal.